How it works
A grid of squares and four colours. Tap a square, or drag across a run of them, and every shape you make is measured as you make it: the area is the squares it covers, the perimeter is the edges round its outside, and both are written on the shape with the outside drawn as a heavy line so what is being counted can be seen. Same-colour squares that touch are one shape; two colours side by side are two. Six squares in a row have a perimeter of 14; the same six as a two-by-three block have a perimeter of 10 — same area, different perimeter, which a child who has coloured both understands without a formula. The Challenge button asks for a shape with a given area AND perimeter, chosen so that it can always be made, and a shape that matches both scores. Each square laid sounds a wooden tock that rises as the shape grows.
Practises
- Area
- Perimeter
- Counting squares and edges
Suited to
Classes 3–6
.