Lesson 5.55.5 Small Group · Group 1
Start hereWords, worked example, and sentence starters
Learning target With my small group, I can find the volume of a rectangular prism with whole-number edges using length × width × height — one step at a time, with support.
Start hereWords for this lesson
Read each word before you begin. Say it out loud.
| Word | What it means | Example |
|---|---|---|
| VolumeSpanish: Volumen | How much space is inside a solid shape. | V = l × w × h |
| Rectangular prismSpanish: Prisma rectangular | A solid box shape with six flat rectangle sides. | a cereal box |
| Cubic unitsSpanish: Unidades cúbicas | The units used to measure space inside, like cubic inches. | cm³, in³, ft³ |
| Length, width, heightSpanish: Largo, ancho, altura | How long, how wide, and how tall a box is. | V = l × w × h: for a box 5 × 3 × 2, volume = 30 cubic units |
| NetSpanish: Plantilla (desarrollo plano) | A flat shape that folds up into a solid. | A cross-shaped pattern of 6 rectangles folds into a rectangular box |
| EdgeSpanish: Arista | The line where two flat sides of a solid meet. | A cube has 12 edges — 4 along the top, 4 along the bottom, 4 vertical |
How it worksWorked examplefinding the volume of a rectangular prism
These numbers are not on your problems. The steps are. Follow them with your own numbers.
A storage box is 8 cm long, 6 cm wide, and 9 cm tall. Find its volume.
- Name the three dimensions. l = 8 cm w = 6 cm h = 9 cm
- Find the base area first — that is one layer of cubes. 8 × 6 = 48
- Stack the layers by multiplying by the height. 48 × 9 = 432
Answer: The volume of the box is 432 cubic centimeters (432 cm³).
Now you trySame steps, your turn
The steps are the same as the worked example. The numbers are yours. Do the work.
A crate is 12 ft long, 7 ft wide, and 10 ft tall. Find its volume.
- Name the three dimensions. l = ft w = ft h = ft
- Find the base area. × = ft²
- Multiply by the height. × = ft³
Say it and write itSentence starters
Finish each sentence out loud with a partner. Then use them in your writing.
- The length is , the width is , and the height is .
- The base area is × = square units.
- The volume is cubic units.
- I used cubic units instead of square units because .
Word bank volumerectangular prismlengthwidthheightbase arealayerunit cubecubic unitsmultiplysolidface
Watch outA common 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. The height must also be multiplied in: V = 6 × 4 × 3 = 72 cubic inches. A second common mistake is adding the three edges instead of multiplying them (6 + 4 + 3 = 13 instead of 6 × 4 × 3 = 72 cubic inches). Volume always MULTIPLIES all three edges, and the answer is always labeled in cubic units (in³), never square units (in²) or plain units (in).
Lesson 5.55.5 Small Group · Group 1
Group 1Supported practice
Learning target With my small group, I can find the volume of a rectangular prism with whole-number edges using length × width × height — one step at a time, with support.
-
1Complete each step, then write the final answer.
Each layer is 4 by 3. There are 2 layers. A box is 4 units long, 3 units wide, and 2 units tall. Find its volume.
- 1How many cubes cover the bottom layer? Multiply 4 × 3.
- 2How many layers are there?
- 3Multiply by the height. What is the volume?
Final answer: -
2Complete each step, then write the final answer.
A box is 7 cm long, 2 cm wide, and 5 cm tall. Find its volume.
- 1Find the area of the base: length × width.
- 2Multiply by the height. What is the volume?
- 3What units does the volume use?
Final answer: -
3Complete each step, then write the final answer.
A box is 3 units long, 3 units wide, and 2 units tall. Find its volume.
Show your workHint Count the cubes in one layer. Then multiply by the number of layers.
Final answer: -
4Complete each step, then write the final answer.
A box is 10 in long, 6 in wide, and 4 in tall. Find its volume.
Show your workHint Use V = l × w × h. Multiply two edges first.
Final answer: -
5Complete each step, then write the final answer.
A time capsule box is 9 inches long, 6 inches wide, and 4 inches tall. How many cubic inches of space are inside?
Show your workHint The space inside is the volume. Multiply all three edges.
Final answer: -
6Complete each step, then write the final answer.
Mo says a box 6 cm long, 2 cm wide, and 3 cm tall has a volume of 11 cubic centimeters, because 6 + 2 + 3 = 11. What is the correct volume?
Show your workHint Mo added the edges. How do you find the number of cubes?
Final answer:
Explain your thinkingWhy do we multiply the three edges and not add them? Use Mo’s mistake and the layers of cubes to explain.
Sentence starter One layer has ___ cubes, and there are ___ layers. · Adding the edges does not work because ___.