0%

Escape the Museum

When disaster strikes at the
Natural History Museum, can you and
your friends use math to escape?
START

YOU DID IT!

Congrats, you escaped the museum and saved the exhibits!
Would you like to play again?

RESTART

Did you know there are many careers that use math
to solve problems and make decisions?
Actuaries are experts who use math to:

Evaluate the likelihood of future events—using numbers, not crystal balls.
Design creative ways to reduce the likelihood of unwanted events.
Decrease the impact of unwanted events that do occur.

Plan Your Visit

Q:

You, Anh, and Jeremiah have purchased three general tickets to the museum, plus three admissions to the special Giant Squid exhibit. The cost for all six tickets was $57. General museum tickets cost $5 more than the admission to the special exhibit. Which equation could you use to figure out how much each friend owes for the Giant Squid exhibit?

a3y + 3(x – 5) = 57 b3x + 3(x + 5) = 57 c6(x + x + 5) = 57 dDon’t know

SUBMIT

Question 1 of 5

Good thinking. That’s the right equation.
That’s not right, but you’ll practice more in the museum.
That’s OK, you’ll get more practice in the museum.
Let’s make a plan, then we can go see the exhibits.

Plan Your Visit

Q:

You, Anh, and Jeremiah have purchased three general tickets to the museum, plus three special admissions to the ecosphere exhibit. The cost for all six tickets was $63. Ecosphere admission costs $3 less than tickets to the museum. Which equation could you use to figure out how much each friend owes for their museum ticket?

a3x + 3y = 63 – 3 ÷ 3 b3x+ 3(x+3)=63 c3x + 3(x – 3) = 63 dDon’t know

SUBMIT

Question 1 of 5

Good thinking. That’s the right equation.
That’s not right, but you’ll practice more in the museum.
That’s OK, you’ll get more practice in the museum.

Plan Your Visit

Q:

Jeremiah wants to see the Giant Squid exhibit on Floor -2 after you’ve finished Pterosaurs on Floor 3. Based on the Floor Directory to the right, which strategy and equation best describe the elevator ride you’d take from Pterosaurs to Giant Squid?

aWe should find the difference between Floor -2 and Floor 3.
-2 – 3 = -5
That means we’d take the elevator down 5 floors.
bWe should find the difference between Floor -2 and Floor 3.
-2 – 3 = |5|
That means we’d take the elevator up 5 floors.
cWe should find the sum of all floors.
-2 + -1 + 0 + 1 + 2 + 3 = 3
That means we’d take the elevator up 3 floors.
dDon’t know

SUBMIT

Question 2 of 5

Perfect. That’ll take you to the exhibit you want to see.
That’s not right, but you’ll practice more in the museum.
That’s OK, you’ll get more practice in the museum.
Perfect. That’ll take you to the exhibit you want to see.
That’s not right, but you’ll practice more in the museum.
That’s OK, you’ll get more practice in the museum.

Plan Your Visit

Q:

Anh wants to check out the nautilus fossil that’s close to 500 million years old! Use the exhibit labels and your knowledge of equivalent expressions to locate the display bookmarked on Anh’s phone.

a b c dDon’t know

SUBMIT

Question 3 of 5

Nice work. Those are the exact specimens we’re looking for!
That’s not right, but you’ll practice more in the museum.
That’s OK, you’ll get more practice in the museum.

Plan Your Visit

Q:

Anh wants to check out the nautilus fossil that’s close to 500 million years old! Use the exhibit labels and your knowledge of equivalent expressions to locate the display bookmarked on Anh’s phone.

a b c dDon’t know

SUBMIT

Question 3 of 5

Nice work. Those are the exact specimens we’re looking for!
That’s not right, but you’ll practice more in the museum.
That’s OK, you’ll get more practice in the museum.
Good work. That route will lead us to the next exhibit!
That’s not right, but you’ll practice more in the museum.
That’s OK, you’ll get more practice in the museum.
Good work. That route will lead us to the next exhibit!
That’s not right, but you’ll practice more in the museum.
That’s OK, you’ll get more practice in the museum.

Plan Your Visit

Q:

How confident are you about knowing which math skill to use to solve math problems?

aVery confident bConfident cSomewhat confident dNot confident

LET’S GO SEE THE DINOS

Question 5 of 5

Nice work. Those are the exact specimens we’re looking for!
That’s not right, but you’ll practice more in the museum.
That’s OK, you’ll get more practice in the museum.
Oh wow, look at that huge fossil.
What’s happening?
It’s an earthquake.
Well, that was…unexpected.
What do we do now?
We’ll get you out in a few seconds. Hang on!
NEED A HINT?
Click on the tool that can help get this fallen fossil back into place.
Let’s get this fallen fossil back into place before the dinosaur skeleton collapses!
We can use the blueprints and the Fossilifter to help us!
Click on the tool that can help us unlock the service elevator.
I bet we can get out of here if we figure out which key unlocks the service elevator.
Wow, that’s a lot of keys to try!
Click on the tool that can help us adjust the temperature.
Let’s see if we can use the knob we found to adjust the temperature!
There’s condensation on the glass. Is it frosting up? That can’t be good for the specimens inside.
Click on the tool that can help us get the power restored.
Let’s grab the flashlight and crack the code.
I think we can get the power restored if we can sort out these wires.

Finish Your Visit

Q:

You, Anh, and Jeremiah found a tumbler online that you decide to buy
from the gift shop. Use the tags on the boxes and your knowledge of
equivalent expressions to pick the box off the shelf that matches the tumbler on the phone.

a b c

SUBMIT

Question 1 of 5

Nice! That’s the right tumbler.
That’s not right, but don’t give up. Keep practicing math!

Finish Your Visit

Q:

You, Anh, and Jeremiah found a tumbler online that you decide to buy
from the gift shop. Use the tags on the boxes and your knowledge of
equivalent expressions to pick the box off the shelf that matches the tumbler on the phone.

a b c

SUBMIT

Question 1 of 5

Nice! That’s the right tumbler.
That’s not right, but don’t give up. Keep practicing math!

Finish Your Visit

Q:

Thanks for visiting! Can you help other museumgoers plan their visit by answering some customer questions?
Customer Question: How much would it cost for my family of four to have snack packs at the cafe?
Pricing Info
Four tickets to the museum plus four snack packs at the café cost $68
Museum tickets cost $7 more than snack packs.

aSnack packs would cost $48 for a family of four.
I used the equation 4x + 4(x – 7) = 68 and proved that x is equal to 12. I multiplied my answer by 4 to find the cost for the whole family.
bSnack packs would cost $20 for a family of four.
I used the equation 4(x + 7) + 4x = 68 to find the cost of a snack pack. I multiplied my answer by 4 to find the cost for the whole family.
cSnack packs are $9.
I divided $72 by four people to get $18, then divided that in half to find the price of snack packs.

SUBMIT

Question 2 of 5

Correct! Thanks for helping other museumgoers.
That’s not right, but don’t give up. Keep practicing math!

Finish Your Visit

Q:

Thanks for visiting! Help other museumgoers plan their visit.
Customer Question: I purchased 6 tickets to the museum plus a t-shirt at the gift shop for my grandson. I need to return the t-shirt because it doesn’t fit. How much is the refund?
Six museum tickets and a t-shirt cost $89. Museum tickets are $5 less than a t-shirt.

aYour refund would be $12.
I used x = the cost of a museum ticket and the equation 6x + x + 5 = 89 to find the answer.
bYour refund would be about $12.75.
I divided $89 by 7 (6 tickets and 1 t-shirt) to get the answer.
cYour refund would be $17.
I used x = the cost of a t-shirt and the equation x + 6(x – 5) = 89 to find the answer.

SUBMIT

Question 2 of 5

Correct! Thanks for helping other museumgoers.
That’s not right, but don’t give up. Keep practicing math!
Correct! Thanks for taking the time to leave your comment and help a fellow museum visitor.
That’s not right, but don’t give up. Keep practicing math!
Correct! Thanks for taking the time to leave your comment and help a fellow museum visitor.
That’s not right, but don’t give up. Keep practicing math!
Correct! Thanks for helping others plan their visit!
That’s not right, but don’t give up. Keep practicing math!

Finish Your Visit

Q:

How confident are you about knowing which math skill to use to solve math problems?

aVery confident bConfident cSomewhat confident dNot confident

NEXT

Question 5 of 5

Nice work. Those are the exact specimens we’re looking for!
That’s not right, but you’ll practice more in the museum.
That’s OK, you’ll get more practice in the museum.

Finish Your Visit

Q:

How much fun was your visit to the museum today?


NEXT

Nice work. Those are the exact specimens we’re looking for!
That’s not right, but you’ll practice more in the museum.
That’s OK, you’ll get more practice in the museum.
Whose reasoning should you follow?

Move 7 units right and
8 units up
Jeremiah

Move 9 units right and
10 units up
Anh

Click on the 3 graph points
Points Found: 0

Attempts (max 5): 0

0
0
Strategy! Let’s visualize the problem as a polygon. Figuring out its base and height will tell us the horizontal and vertical distance the Fossilifter needs to travel.
Using straight lines to connect the points makes a triangle with the coordinates (-8, -9) and (1, 1) and (1, -9).
Click on the graph to plot the points.

Reasoning!
Let’s use subtraction to find the difference between the coordinates on the x and y axes. I’ll go left to right on the coordinate plane, since equations are written left to right.
On the x-axis,
-8 minus 1 is -7. Since this is a length indicating real space at the museum, I’ll use the absolute value of 7.
On the y-axis, -9 minus 1 is -8, or 8 in absolute value.
Therefore! If we reasoned correctly, we need to set the Fossilifter to move the femur 7 units right on the x-axis and 8 units up on the y-axis.
Strategy! Let’s think of the problem like a polygon. The lengths its base and height are the distances the Fossilifter needs to travel horizonally and vertically. I see the polygon as a triangle with these coordinates: (-8, -9) and (1, 1) and (1, -9).
Click on the graph to plot the points.

Reasoning! How can we find the lengths of the triangle’s base and height? If we use subtraction, we can find the difference between the two x coordinates and the two y coordinates that make up each side.
I’ll start with the bigger number and subtract the smaller one, since distance must be a positive number. On the x-axis, 1 minus -8 means that the triangle’s base is 9 units long, because subtracting a negative number is equivalent to adding a positive number.
On the y-axis, 1 minus -9 means that the triangle’s height is 10 units.
Therefore! If our calculations are right, we need to set the Fossilifter to move the femur 9 units right on the x-axis and 10 units up on the y-axis.
Set the Fossilifter to see if that’s right!
Set the Fossilifter to see if that’s right!
Perfect! The fossil is back where it belongs.
Let’s see if there’s another area we can fix.
Uh oh! That’s not where the fossil belongs.
We gotta keep our heads in the game.

Let’s try to fix another fossil.

Fix the Fossil

The femur fossil has tumbled to (-8, -9). We need to get it back into place at (1, 1). How many horizontal and vertical units do we need to move it? Listen to Anh and Jeremiah’s solutions to choose the best option.

Anh’s Solution


Strategy! Let’s think of the problem like a triangle with these coordinates: (-8, -9) and (1, 1) and (1, -9). Click here to show the points.

Reasoning!
Let’s subtract to find the difference between the two x coordinates and the two y coordinates that make up each side. I’ll start with the bigger number and subtract the smaller one, since distance must be a positive number.
On the x-axis, 1 minus -8 means that the triangle’s base is 9 units long.
On the y-axis, 1 minus -9 means that the triangle’s height is 10 units, because subtracting a negative number is equivalent to adding a positive number.

Therefore! We need to move the femur 9 units right on the x-axis and 10 units up on the y-axis.
Choose a solution


Jeremiah’s Solution


Strategy! Let’s visualize the problem as a triangle with coordinates (-8, -9) and (1, 1) and (1, -9). Click here to show the points. Figuring out the triangle’s base and height will tell us the distances the Fossilifter needs to travel.

Reasoning!
Let’s subtract to find the difference between the coordinates on the x and y axes. I’ll go left to right on the coordinate plane, since equations are written left to right.
On the x-axis, -8 minus 1 is -7. Since this is a length indicating real space at the museum, I’ll use the absolute value of 7.
On the y-axis, -9 minus 1 is -8, or 8 in absolute value.

Therefore! If we reasoned correctly, we need to set the Fossilifter to move the femur 7 units right on the x-axis and 8 units up on the y-axis.
Choose a solution

Fix the Fossil

The femur fossil has tumbled to (-8, -9). We need to get it back into place at (1, 1). How many horizontal and vertical units do we need to move it? Listen to Anh and Jeremiah’s solutions to choose the best option.
START

KEEP GOING
Whose reasoning should you follow?

Move 6 units right and
8 units up
Jeremiah

Move 8 units right and
6 units up
Anh

Click on the 3 graph points
Points Found: 0

Attempts (max 5): 0

0
0
Strategy! Let’s think of the problem like a polygon. The lengths of its base and height will tell us the distance the Fossilifter needs to travel horizontally and vertically.
I see the polygon as a triangle with these coordinates: (-3, -7) and (3, 1) and (3, -7).
Click on the graph to plot the points.

Reasoning! How can we find the lengths of the triangle’s base and height? If we use subtraction, we can find the difference between the coordinates on each axis.
Which number should go first in each equation? Since distance must be a positive number, I’ll start with the bigger number and subtract the smaller one.
For the base, I see the two x coordinates are: -3 and 3.
I’ll start my equation with positive 3 because it’s the bigger number.
3 minus -3 means that the base is 6 units.
On the y-axis, 1 minus -7 means that the height is 8 units.
Therefore! I think that means we need to set the Fossilifter to move the fossil 6 units right on the x-axis and 8 units up on the y-axis.
Strategy! Let’s visualize the problem as a polygon. The lengths of its imaginary sides will tell us the distance the Fossilifter needs to travel horizontally and vertically.
Using straight lines to connect the points makes a triangle with the coordinates (-3, 1) and (3, 1) and (-3, -7).
Click on the graph to plot the points.

Reasoning! Let’s find the difference between the coordinates on the x- and y-axes using subtraction.
For the base, 3 minus -3 gives us a distance of 6 units.
For the height, 1 minus -7 is a distance of 8 units.
Therefore! I think we should set the Fossilifter to move the fossil 8 units right on the x-axis and 6 units up on the y-axis.
Set the Fossilifter to see if that’s right!
Set the Fossilifter to see if that’s right!
Perfect! The fossil is back where it belongs.
Let’s see if there’s another area we can fix.
We’ll just have to move on and learn from our mistakes.
Ugh, that didn’t work.

Fix the Fossil

The fallen fossil has tumbled to (-3, -7). We need to get it back into place at (3, 1). How many horizontal and vertical units do we need to move it? Set the Fossilifter’s vertical and horizontal commands! Review Anh and Jeremiah’s reasoning and choose the correct solution.

Anh’s Solution


Strategy! Let’s visualize the problem as a triangle with the coordinates (-3, 1) and (3, 1) and (-3, -7). Click here to show the points.

Reasoning! Let’s find the difference between the coordinates on the x- and y-axes using subtraction.
For the base, 3 minus -3 gives us a distance of 6 units.
For the height, 1 minus -7 is a distance of 8 units.

Therefore! I think we should set the Fossilifter to move the fossil 8 units right on the x-axis and 6 units up on the y-axis.
Choose a solution


Jeremiah’s Solution


Strategy! Let’s think of the problem like a triangle with coordinates (-3, -7) and (3, 1) and (3, -7). Click here to show the points.

Reasoning!
If we use subtraction, we can find the difference between the coordinates on each axis. In each equation, since distance must be a positive number, I’ll start with the bigger number and subtract the smaller one.
For the base, I see the two x coordinates are: -3 and 3. I’ll start my equation with positive 3 because it’s the bigger number. 3 minus -3 means that the base is 6 units.
On the y-axis, 1 minus -7 means that the height is 8 units.

Therefore! I think that means we need to set the Fossilifter to move the fossil 6 units right on the x-axis and 8 units up on the y-axis.
Choose a solution

Fix the Fossil

The fallen fossil has tumbled to (-3, -7). We need to get it back into place at (3, 1). How many horizontal and vertical units do we need to move it? Set the Fossilifter’s vertical and horizontal commands! Review Anh and Jeremiah’s reasoning and choose the correct solution.
START

KEEP GOING
Whose reasoning should you follow?

Plug the wire into
-y + 7x + 14x – 12y – 15y
Jeremiah

Plug the wire into
7(3x – 3y + y)
Anh

21x – 28y -y + 7x + 14x – 12y – 15y 7(3x – 3y + y)
Strategy! I think I know which socket to plug the wire into. Let’s try reorganizing the expression by collecting like terms to see if I’m right.
Reasoning! First, I’m going to shuffle things around so I can put all of the x’s and y’s together.
Then I’ll combine like terms by adding and subtracting.
Therefore! If I simplified the terms correctly, that means 21x – 28y is equivalent to -y + 7x + 14x – 12y – 15y.
Strategy! I’m pretty sure the second expression is the equivalent one. Let’s try collecting like terms to see if I’m right.
Reasoning! First, we’ll combine like terms by adding 3y and y.
Then, we’ll multiply each of the terms inside the parentheses by 7.
3x multiplied by 7 is 21x and 4y multiplied by 7 is 28y.
Therefore! I think we should plug the wire labeled 21x – 28y into 7(3x – 3y + y) because we’ve shown it’s equivalent.
Drag the wire into that socket to see if we’re right!
Drag the wire into that socket to see if we’re right!
Yes! That was the right socket!
Whoooo, the power is restored!
Okay, let’s try one more time with a different set of wires.
That didn’t work. I guess we are still in the dark.

Fix the Electricity

In the earthquake, the museum lost power.
To restore power,
plug the wire into the
socket labeled with the
equivalent expression.

Listen to Anh and
Jeremiah’s reasoning and
choose the best solution.

Jeremiah’s Solution


Strategy! Let’s reorganize the expression -y + 7x + 14x -12y -15y by collecting like terms.

Reasoning!
First, I’m going to shuffle things around so I can put all of the x’s and y’s together.
I get 14x + 7x – 15y – 12yy.
Then I’ll combine like terms by adding and subtracting, which results in 21x – 28y.

Therefore! I found that 21x – 28y is equivalent to -y + 7x + 14x – 12y – 15y.
Choose a solution


Anh’s Solution


Strategy! Let’s collect like terms in the expression 7(3x – 3y + y).

Reasoning!
First, we’ll combine like terms within the parentheses by adding 3y and y.
Then, we’ll multiply each of the terms inside the parentheses by the 7 outside the parenthesis.
3x multiplied by 7 is 21x.
4y multiplied by 7 is 28y.

Therefore! We should plug the wire labeled 21x – 28y into 7(3x – 3y + y).
Choose a solution

Fix the Electricity

In the earthquake, the museum lost power. To restore power, plug the wire into the socket labeled with the equivalent expression. Review Anh and Jeremiah’s reasoning and choose the best solution.
START

KEEP GOING
Whose reasoning should you follow?

Plug the wire into
3(2x + 3y)
Jeremiah

Plug the wire into
6(x + 3y)
Anh

6x + 9y 3(2x + 3y) 6(x + 3y)
Strategy! I think I know which is the equivalent expression.
Let’s try using the distributive property to see if I’m right.
Reasoning! First, we’ll multiply 2x by 3 to get 6x.
Then, we’ll multiply 3y by 3 to get 9y.
Therefore! If I multiplied everything right, I think we should plug 6x + 9y into 3(2x + 3y) because they’re equivalent expressions.
Strategy! I think I know which socket to plug the wire into. Let’s expand the expression to see if I’m right.
Reasoning! First, I’ll add 6 and x to get 6x.

Then, I’ll add 6 and 3y to get 9y.
Therefore! If I
did the addition correctly, we should plug 6x + 9y into 6(x +3y) because they’re equivalent expressions.
Drag the wire into that socket to see if we’re right!
Drag the wire into that socket to see if we’re right!
Yes! That was the right socket!
Whoooo, the power is restored!
Don’t give up!
Let’s look around for something else to fix.
That didn’t work. I guess we’re still in the dark.

Fix the Electricity

In the earthquake, the museum lost power.
To restore power,
plug the wire into the
socket labeled with the
equivalent expression.

Listen to Anh and
Jeremiah’s reasoning and
choose the best solution.

Jeremiah’s Solution


Strategy! Let’s use the distributive property on the socket labeled
3(2x +3y).

Reasoning!
First, multiply 2x by 3 to get 6x.
Then, multiply 3y by 3 to get 9y.

Therefore! I think we should plug 6x + 9y into 3(2x +3y) because they’re equivalent expressions.
Choose a solution


Anh’s Solution


Strategy! I’ll expand the expression 6(x + 3y).

Reasoning!
First, I’ll add 6 and x to get 6x.
Then, I’ll add 6 and 3y to get 9y.

Therefore! If I did the addition correctly, we should plug 6x + 9y into
6(x + 3y) because they’re equivalent expressions.
Choose a solution

Fix the Electricity

In the earthquake, the museum lost power. To restore power, plug the wire into the socket labeled with the equivalent expression. Review Anh and Jeremiah’s reasoning and choose the best solution.
START

KEEP GOING
Whose reasoning should you follow?

4 brass keys
Jeremiah

6 brass keys
Anh

Strategy! Let’s write an algebraic expression and use k to stand in for the number of keys we need to try in the lock.
Reasoning! First, we’ll establish that there are 48 keys in total.
On the right side of the equation, we’ll represent the silver and gold keys (3 times silver and 4 times gold).
Then we’ll multiply everything in the parentheses by the variable (since silver and gold keys are 3 times and 4 times the unknown variable).
If we combine like terms, we end up with 48 equals 12k. After we use division to isolate the variable k, we get 4.
Therefore! We’ll be able to unlock the elevator if we try, at most, 4 brass keys.
Strategy! Let’s set up an algebraic equation to find out how many brass keys are on the ring.
Reasoning! First, we’ll establish that b stands for the number of brass keys.
Then we’ll write an equation: Silver keys plus gold keys is equal to the total number of keys on the ring minus the brass keys—that’s the number of keys we might need to try in the lock!
If we use addition to combine like terms, we end up with 8b equals 48. After we use division to isolate the variable b, we get b equals 6.
Therefore! I think we can unlock the elevator if we try up to 6 brass keys.
Drag the key to that number to see if we tried enough keys in the lock!
Drag the key to that number to see if we tried enough keys in the lock!
We’ll get the elevator unlocked in no time!
That’s the right number of keys!
Hmmm, that didn’t work.
Don’t give up hope, there’s another lock and set of keys we can try!

Fix the Exit

Jeremiah has tried all of the silver and gold keys on the key ring without any luck. By process of elimination, that means the key that unlocks the service elevator must be a brass key! What is the maximum number of keys Jeremiah might need to try in the lock? Review Anh and Jeremiah’s reasoning and choose the correct solution.

Jeremiah’s Solution


Strategy! Let’s write an algebraic expression and use k to stand in for the number of keys we need to try in the lock.

Reasoning!
First, we’ll establish that there are 48 keys in total.
On the right side of the equation, we’ll represent the silver and gold keys (3 times silver and 4 times gold). That’s 48 = (3 x 4) x k.
Then we’ll multiply everything in the parentheses by the variable k (since silver and gold keys are 3 times and 4 times the unknown variable).
If we combine like terms, we end up with 48 equals 12k.
After we use division to isolate the variable k, we get 4.

Therefore! We’ll be able to unlock the elevator if we try, at most, 4 brass keys.
Choose a solution


Anh’s Solution


Strategy! Let’s set up an algebraic equation.

Reasoning!
First, we’ll establish that b stands for the number of brass keys.
Then we’ll write an equation: Silver keys plus gold keys is equal to the total number of keys on the ring minus the brass keys. That’s 3b + 4b = 48 - b.
If we use addition to combine like terms, we end up with 8b equals 48.
After we use division to isolate the variable b, we get 6.

Therefore! We can unlock the elevator if we try up to 6 brass keys.
Choose a solution

Fix the Exit

Jeremiah has tried all of the silver and gold keys on the key ring without any luck. By process of elimination, that means the key that unlocks the service elevator must be a brass key! What is the maximum number of keys Jeremiah might need to try in the lock? Review Anh and Jeremiah’s reasoning and choose the correct solution.
START

KEEP GOING
Whose reasoning should you follow?

2 gold keys
Jeremiah

4 gold keys
Anh

Strategy! Let’s write an algebraic equation and use g to stand in for the number of keys we need to try in the lock.
Reasoning!
Let’s set up parentheses to represent the silver and brass keys (5 times and 4 times). We’ll make the right side of the equation equal to 40—the total number of keys on the ring.
Next we’ll multiply everything in the parentheses by the variable (since silver keys are 5 times the unknown variable and brass keys are 4 times the unknown variable).
Finally, we’ll multiply the g terms together to get 20g. When we solve for g we get 2.
Therefore! We should be able to unlock the elevator if we try 2 gold keys.
Strategy! We should think of the number of gold keys like an unknown variable!
Reasoning! If we subtract the number of silver keys and the number of brass keys from the total number of keys, we’ll be left with the number of gold keys! Let’s set up an equation.
I’ll start the equation with the number of keys. k represents the number of gold keys. Silver is 5k (5 times gold keys) and brass is 4k (4 times gold keys).
If we combine like terms, we end up with 40 equals 10k.
After we use division to isolate the variable k, we get 4.
Therefore! If we set up the equation correctly, we need to try 4 gold keys in the elevator!
Drag the key to that number to see if we tried enough keys in the lock!
Drag the key to that number to see if we tried enough keys in the lock!
We’ll get the elevator unlocked in no time!
That’s the right number of keys!
That wasn’t right, but we learned what doesn’t work.
So we’ll be more prepared in the future!

Fix the Exit

You’ve found another set of keys. Anh has tried all of the brass and silver keys without any luck. That means the key that unlocks the service elevator must be a gold key! How many more keys does your group need to try in the lock? Listen to Anh and Jeremiah’s solutions to choose the best option.

Jeremiah’s Solution


Strategy! Let’s write an algebraic equation and use g to stand in for the number of keys we need to try in the lock.

Reasoning!
Let’s set up parentheses to represent the silver and brass keys (5 times and 4 times).
We’ll make the right side of the equation equal to 40—the total number of keys on the ring.
That’s (5 x 4) x g = 40.
Next we’ll multiply everything in the parentheses by the variable g (since silver keys are 5 times the unknown variable and brass keys are 4 times the unknown variable). That’s 5g x 4g = 40.
Finally, we’ll multiply the g terms together to get 20g. When we solve for g we get 2.

Therefore! We should be able to unlock the elevator if we try 2 gold keys.
Choose a solution


Anh’s Solution


Strategy! We should think of the number of gold keys like an unknown variable.

Reasoning! If we subtract the number of silver keys and the number of brass keys from the total number of keys, we’ll be left with the number of gold keys! Let’s set up an equation.
I’ll start the equation with the number of keys, 40.
I’ll have k represent the number of gold keys.
Silver is 5k (5 times gold keys) and brass is 4k (4 times gold keys).
That’s 40 – 5k – 4k = k.
If we combine like terms, we end up with 40 equals 10k.
After we use division to isolate the variable k, we get 4.

Therefore! If we set up the equation correctly, we need to try 4 gold keys in the elevator!
Choose a solution

Fix the Exit

You’ve found another set of keys. Anh has tried all of the brass and silver keys without any luck. That means the key that unlocks the service elevator must be a gold key! How many more keys does your group need to try in the lock? Listen to Anh and Jeremiah’s solutions to choose the best option.
START

KEEP GOING
Whose reasoning should you follow?

Turn up
45
degrees
Jeremiah

Turn up
35
degrees
Anh

-5
Strategy! Let’s think of the temperature control like a number line.
Reasoning! On the negative side of the number line, the difference between -5 and 0 is -5, or 5° in absolute value.
On the positive side, the difference between 0 and 40 is 40°.
If we add 5° and 40° together, we get a total of 45°.
Therefore! I think we need to turn the temperature control knob up by 45°.
Strategy! Let’s find the difference between the temperatures using subtraction.
Reasoning!
If we take 40° and subtract negative 5°, we get 35°.
Therefore! We need to turn the temperature up by 35°.
Drag the control knob onto the display case to see if you’re right.
Drag the control knob onto the display case to see if you’re right.
YES! The temperature inside the display is back to normal.
Now that the insects are safe, let’s find another area to fix!
Stay focused. There’s another display we can try to save.
Uh oh! We must have miscalculated.

Fix the Temperature

The temperature inside the insect display is –5 °F. It should be set to 40°F.
How many degrees should you and your friends turn the knob in order to return to the correct temperature? Review Anh and Jeremiah’s reasoning and choose the correct solution.

Jeremiah’s Solution


Strategy! Let’s think of the temperature control like a number line.

Reasoning!
On the negative side of the number line, the difference between -5 and 0 is -5, or 5° in absolute value.
On the positive side, the difference between 0 and 40 is 40°.
If we add 5° and 40° together, we get a total of 45°.

Therefore! I think we need to turn the temperature control knob up by 45°.
Choose a solution


Anh’s Solution


Strategy! Let’s find the difference between the temperatures using subtraction.

Reasoning! If we take 40° and subtract negative 5°, we get 35°.

Therefore! We need to turn the temperature up by 35°.
Choose a solution

Fix the Temperature

The temperature inside the insect display is -5 °F. It should be set to 40°F.
How many degrees should you and your friends turn the knob in order to return to the correct temperature? Review Anh and Jeremiah’s reasoning and choose the correct solution.
START

KEEP GOING
Whose reasoning should you follow?

Turn down
80
degrees
Jeremiah

Turn down
60
degrees
Anh

70
Strategy! Let’s use subtraction to find the difference between the two temperatures.
Reasoning! To get from 70° to -10°, I need to use subtraction. That will give me two negative signs in a row.
Subtracting a negative number is the same as adding a positive. So 70° – (-10°) becomes 70° plus 10°, which is 80°.
Therefore! I think we need to turn the temperature down by 80°.
Strategy! Let’s use addition to move from one temperature to another.
Reasoning!
I’ll combine the current temperature of 70° with the goal temperature of -10°, which will tell me how much to move the control dial. 70° plus -10° is 60°.
Therefore! I believe we should turn down the temperature by 60°.
Drag the control knob onto the display case to see if you’re right.
Drag the control knob onto the display case to see if you’re right.
YES! The temperature inside the display is back to normal.
Now that the insects are safe, let’s find another area to fix!
Maybe there’s a different way we can help the museum.
Oops, that didn’t work.

Fix the Temperature

The butterfly display case is also fogging up! The temperature inside the display is 70 °F. It should be set to
-10 °F. By how many degrees does the temperature need to be adjusted? Review Anh and Jeremiah’s reasoning and choose the correct solution.

Jeremiah’s Solution


Strategy! Let’s use subtraction to find the difference between the two temperatures.

Reasoning!
To get from 70° to -10°, I need to use subtraction, 70° – (-10°). That gives me two negative signs in a row.
Subtracting a negative number is the same as adding a positive.
So 70° – (-10°) becomes 70° + 10°, which is 80°.

Therefore!
We need to turn the temperature down by 80°.
Choose a solution


Anh’s Solution


Strategy! Let’s use addition to move from one temperature to another.

Reasoning!
I’ll combine the current temperature of 70° with the goal temperature of -10°, which will tell me how much to move the control dial. 70° plus -10° is 60°.

Therefore!
We should turn down the temperature by 60°.
Choose a solution

Fix the Temperature

The butterfly display case is also fogging up! The temperature inside the display is 70 °F. It should be set to -10 °F. By how many degrees does the temperature need to be adjusted? Review Anh and Jeremiah’s reasoning and choose the correct solution.
START

KEEP GOING