6.GR.2 Group 2 · Challenge

Practice Set · Part 1

Determine the Volume of Rectangular Prisms

Pick up where we left off

Name: Date: Group:

Where we left off

Our goal: I can find the volume of a rectangular prism with whole-number edges using length × width × height, explain why the method works, and use it on a problem I have not seen before.

The big idea: Volume is base area times height, so dividing the volume by the base area tells how many layers tall the box is.

Model to copy — Example · Find a missing height

  1. A storage box has a volume of 120 cubic inches. It is 6 inches long and 5 inches wide. How tall is it?
  2. Find the area of the base: 6 × 5 = 30
  3. Write the volume with the missing height: 120 = 30 × h
  4. Divide the volume by the base area: 120 ÷ 30 = 4
  5. Check by multiplying: 6 × 5 × 4 = 120
  6. The box is 4 inches tall.

Start here

You did these with your group. Now do them on your own — the model above is yours to copy.

  1. 1

    Same stepsFinish what the group started. Use the model above, step for step.

    Try it together — then prove it: A box is 5 units long, 2 units wide, and 2 units tall. Find its volume. Find the volume. (5 × 2 × 2 = 20 cubic units) How many cubes are in one layer? How many layers? (10 cubes in a layer, and 2 layers) Why is the answer in cubic units, not square units? (Volume fills space in 3 directions: length, width and height. Each unit is a small cube.)
    Show your work
  2. 2

    Warm restartTo find the area of a composite figure, you first…

    1. Ameasure around the outside
    2. Bmultiply all the side lengths
    3. Cfind the longest side
    4. Dbreak it into basic shapes you know

    How do you know?

  3. 3

    Warm restartA figure is a 6 by 4 rectangle with a 2 by 3 rectangle attached. What is the total area?

    1. A15 square units
    2. B24 square units
    3. C30 square units
    4. D144 square units

    How do you know?

  4. 4

    Warm restartA 10 by 8 rectangular garden has a 3 by 3 square patio cut out of it. What area is left?

    1. A62 square units
    2. B71 square units
    3. C80 square units
    4. D89 square units

    How do you know?

5.5 Small Group · Group 2 · Practice SetPart 1 of 4
6.GR.2 Group 2 · Challenge

Practice Set · Part 2

Determine the Volume of Rectangular Prisms

Keep going

You answered these out loud. Now write them.

Answer, then say how you know — the reason is the part that counts.

  1. 5

    Think it throughWhat is the volume of the large box?

    1. A60 in³
    2. B3,024 in³
    3. C4,752 in³
    4. D7,776 in³

    Why is that the answer?

  2. 6

    Think it throughWhat is the volume of the medium box?

    1. A2,520 in³
    2. B3,024 in³
    3. C3,240 in³
    4. D4,752 in³

    How do you know? Give a second reason as well.

  3. 7

    Think it throughHow many more cubic inches does the large box hold?

    1. A1,728 in³
    2. B3,024 in³
    3. C4,752 in³
    4. D10,800 in³

    Explain your thinking. What would have to change for a different choice to be right?

  4. 8

    Back to the modelContainer C holds the most (96 in³) and Container B holds the least (50 in³). What do you notice about the dimensions that make one volume larger than another?

5.5 Small Group · Group 2 · Practice SetPart 2 of 4
6.GR.2 Group 2 · Challenge

Practice Set · Part 3

Determine the Volume of Rectangular Prisms

Words and reasoning

Word bank · Banco de palabras

Volume (Volumen)Rectangular prism (Prisma rectangular)Cubic units (Unidades cúbicas)Length, width, height (Largo, ancho, altura)Net (Plantilla (desarrollo plano))Edge (Arista)Unit cube (Cubo unitario)

Use the words

Fill each blank with a word from the bank.

Explain the thinking

  1. 9

    Find the mistakeAnother student made this exact mistake in this lesson. Explain why it is wrong, then write what they should have done.

    The mistake: A common mistake in Volume with Whole Number Edges is multiplying only two of the three edges and stopping there — for example, seeing a box that is 6 in long, 4 in wide, and 3 in tall, multiplying just 6 × 4 = 24, and calling that the volume, when 24 is only the area of the bottom face (in square inches), not the volume of the whole box.
  2. 10

    Say moreContainer C is 8 × 3 × 4 and Container B is 5 × 5 × 2. How did you count or multiply the unit cubes to find each volume, and which holds more?

  3. 11

    Write your ownWrite your own problem about this situation, then solve it and show the answer. The situation: Two time capsule containers sit side by side. Capsule A is 4 in long, 3 in wide, and 8 in tall. Capsule B is 6 in long, 6 in wide, and 6 in tall. A classmate says Capsule A must hold more because it looks taller.

    Show your work
5.5 Small Group · Group 2 · Practice SetPart 3 of 4
6.GR.2 Group 2 · Challenge

Practice Set · Part 4

Determine the Volume of Rectangular Prisms

Show what you know

Last check

These two come from Lesson 5.4. If they are shaky, that is the lesson to revisit — not this one.

  1. 12

    Show what you knowExplain your thinking — A rectangular prism has l = 11 in, w = 5 in, h = 4 in. What is the volume?

    1. A55 in³
    2. B200 in³
    3. C220 in³
    4. D220 in²

    Explain your choice.

  2. 13

    From Lesson 5.4Explain your thinking — A composite figure is made of a 9 ft x 7 ft rectangle and a 3 ft x 4 ft rectangle joined together. What is the total area?

    1. A12 sq ft
    2. B63 sq ft
    3. C75 sq ft
    4. D75 ft

    How do you know?

  3. 14

    From Lesson 5.4What will the carpet cost?

    1. A$116
    2. B$300
    3. C$580
    4. D$1,160

    How do you know?

Be honest — this tells your teacher what to do next

I can…Not yetGetting thereGot it
I can find the volume of a rectangular prism with whole-number edges using length × width × height, explain why the method works, and use it on a problem I have not seen before.
I can explain why it works: Volume is base area times height, so dividing the volume by the base area tells how many layers tall the box…
I can justify my answer to a skeptic and connect it to a second strategy or representation.

One question I want to ask my group next time