The Life Starter
Sign up
Grade 1 · lesson 4 of 4

Describe a Piece and the Composite Whole

Read the stated cut or composition.

About 15 minutes, plus any extended practice

Download the grade pack

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 square is cut along its diagonal.
  • All quantities and shape descriptions are supplied in the worked example and questions; no purchase or personal information is needed.

Learn the idea

A piece can keep its own shape name while belonging to a differently named whole. For example, triangular pieces can build a square. Naming the whole does not make each individual piece a square. Keep separate descriptions for the parts and for their complete outside outline.

Read the stated cut or composition. Identify one component’s shape and then identify the rebuilt whole. Explain which boundary you used for each name so that parts and whole are not confused.

Trace the piece’s boundary separately from the whole’s outline. A composite’s name does not automatically name each part. Use different patterns to label pieces, then trace the whole with one bold outline.

  1. Use different patterns to label pieces, then trace the whole with one bold outline.
  2. Follow the worked example. Point to each number or shape feature and say what it tells you.
  3. Read the stated cut or composition.
  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 square is cut along its diagonal. Each of the two pieces is a triangle, but their joined outer outline is a square. The component names describe three-sided pieces; the whole’s name describes the four-sided outer boundary with equal sides and right angles. Trace the piece’s boundary separately from the whole’s outline. A composite’s name does not automatically name each part. Use different patterns to label pieces, then trace the whole with one bold outline.

Your turn

Check your reasoning

Your answer is temporary and is not saved to an account. Download your current answer before leaving or reloading. Written work on paper or in another app stays in your own file.

Helpful tips
  • Trace the piece’s boundary separately from the whole’s outline.
  • A composite’s name does not automatically name each part.
A square is cut along a diagonal. What is each piece?

Feedback appears here after you check. This is practice, not a graded school assessment.

See the answer and explanation

Triangle

Each component has three straight sides.

Take it further

Describe the pieces and whole of a rectangle split by a diagonal. Expected: two triangles; rebuilt rectangle.

Nothing here is saved to an account or sent to a teacher. The answer download includes your current choice and any checked feedback. It does not include choices from the separate More practice section. Download that section separately.

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. Two semicircles join along their straight edges. What is the whole?
Need a hint?
  • Trace the piece’s boundary separately from the whole’s outline.
  • A composite’s name does not automatically name each part.
2. Two equal squares join side by side. What is each component?
Need a hint?
  • Trace the piece’s boundary separately from the whole’s outline.
  • A composite’s name does not automatically name each part.
3. Two equal squares join side by side. What is the whole outline?
Need a hint?
  • Trace the piece’s boundary separately from the whole’s outline.
  • A composite’s name does not automatically name each part.

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

Nothing here is saved to an account or sent to a teacher. Keep your own notes or download them before leaving. The score describes these questions; it does not certify subject mastery.

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.