Compound Shapes Area – Colour by Number Activity

Students calculate the area of compound (composite) shapes by decomposing them into simpler figures.

Students apply a computed numeric answer to a colour-matching key rather than writing the number directly.

Students self-check their area calculations, since an error produces a visibly incorrect colour-by-number result.

Have students show their area-decomposition work for each of the 10 shapes on a separate sheet before transferring only the colour to the grid, since the colour-by-number format hides individual numeric answers.

Use the answer key to spot-check a student's colouring quickly against the expected area-to-colour pairing rather than re-solving every shape.

Assign the activity as independent practice after direct instruction on decomposing compound shapes into rectangles and triangles, since the worksheet itself provides no worked example.

Compound-shape area calculation — students decompose 10 composite figures into simpler shapes to compute area.

Self-checking through colour-by-number — students verify their arithmetic because an incorrect area produces a visibly wrong colour in the revealed picture.

Precision and unit tracking — students track area values in square centimeters across ten distinct problems.