Grade 5 · lesson 3 of 4

Add Volumes of Non-Overlapping Prisms

Calculate each supplied length × width × height product.

About 25 minutes, plus any extended practice

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Supplied materials

  • Paper and a pencil; drawing and spoken explanations are welcome. An adult may read directions and options aloud.
  • Supplied worked-case record: A solid has adjoining prisms 4×3×2 and 2×3×5 units with no interior overlap.
  • All quantities and shape descriptions are supplied in the worked example and questions; no purchase or personal information is needed.

Learn the idea

A solid can be decomposed into rectangular prisms with non-overlapping interiors. Compute each prism’s volume and add the results. Shared faces have no volume, but an overlapped block would be counted twice. The stated decomposition must include the full solid.

Calculate each supplied length × width × height product. Add the volumes because the exercise explicitly states no interior overlap. Check unit consistency and distinguish a shared face from an overlapped three-dimensional region.

Verify the supplied non-overlap condition. Do not add an extra amount for the shared joining face. Pattern the two solid parts differently and list each volume before adding.

  1. Pattern the two solid parts differently and list each volume before adding.
  2. Follow the worked example. Point to each number or shape feature and say what it tells you.
  3. Calculate each supplied length × width × height product.
  4. Try the question and then the three practice questions. Check your answers and explain any change you make.
Worked example

See the method in action

A solid has adjoining prisms 4×3×2 and 2×3×5 units with no interior overlap. Their volumes are 24 and 30 cubic units, totaling 54. The joining face does not add volume. If a real overlap existed, direct addition would count its cubes twice. Verify the supplied non-overlap condition. Do not add an extra amount for the shared joining face. Pattern the two solid parts differently and list each volume before adding.

Your turn

Check your reasoning

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Helpful tips
  • Verify the supplied non-overlap condition.
  • Do not add an extra amount for the shared joining face.
A solid consists of non-overlapping prisms 2×3×2 and 2×2×4 units. What is the total volume?

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See the answer and explanation

28

Add the two complete prism volumes; their interiors do not overlap. The result is 28.

Take it further

Non-overlapping 5×4×2 and 3×2×6 prisms have total volume 76 cubic units.

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More practice: try new cases

Choose an answer for each problem. Explain your method on paper, then use the feedback to decide what to revisit.

More practice: try new cases
1. A solid consists of non-overlapping prisms 3×3×2 and 2×2×4 units. What is the total volume?
Need a hint?
  • Verify the supplied non-overlap condition.
  • Do not add an extra amount for the shared joining face.
2. A solid consists of non-overlapping prisms 4×3×2 and 2×2×4 units. What is the total volume?
Need a hint?
  • Verify the supplied non-overlap condition.
  • Do not add an extra amount for the shared joining face.
3. A solid consists of non-overlapping prisms 5×3×2 and 2×2×4 units. What is the total volume?
Need a hint?
  • Verify the supplied non-overlap condition.
  • Do not add an extra amount for the shared joining face.

Your choices are temporary. Feedback appears after you check all the answers.

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Check the subject sources

These LifeStarter passages, scenarios and exercises are authored for this Academy with AI assistance and review. External resources keep their publishers’ terms. A grade label suggests a starting level; it does not establish alignment with your school’s complete requirements.