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P3 Rectangle and square measurement

distinguish area from perimeter

The shown 7-by-4 rectangle is covered with square tiles. Does the number of tiles describe its area or its perimeter?

A rectangle with its side lengths marked.7 cm4 cm
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area

One step of the worked solution to distinguish area from perimeter, drawn in pencil.
5 steps, drawn in pencil

The pattern behind it: Rectangle and square measurement

Use opposite equal sides, undo the area or perimeter formula, and count each outside edge once.

In this one. Area counts square units covering a surface, while perimeter measures distance around its edge.

Undo or tracearea48 split into rows of 8 gives width 6perimeterfour equal square sides

How to spot it

Squares tiling a rectangle, or a shape made of several rectangles joined together, point here. The question asks for area, perimeter, or the length of a missing side.

Common mistake

Children multiply length by width when the question actually asks for perimeter. On a composite shape, they add only the labelled sides and miss the ones they must work out themselves.

Try one like it

Standard distinguish area from perimeter The shown 8-by-5 rectangle is covered with square tiles. Does the number of tiles describe its area or its perimeter?
All 14 with this pattern →

The 33 problem patterns

All 33 patterns, one to a page — the 19 behind Primary 5 and 6 word problems, and the skills the younger years are built on. The bar model, how to spot it in the question, and the mistake children make. A booklet you can print. Free.

A PDF, and a note when new solutions go up.