Why Shikaku works for kids
The rule is one sentence, there is no reading load, and progress is visible: every rectangle is a small win. Mistakes are easy to undo, and because each puzzle has exactly one answer, children can check their own work.
Skills it practises
- Area — counting the cells in a rectangle, then multiplying instead of counting.
- Factor pairs — “which rectangles have an area of 12?”
- Logical reasoning — explaining why a rectangle must go somewhere.
- Spatial thinking — seeing shapes fit together.
- Persistence — working through a puzzle step by step.
Getting started
| Stage | Suggested puzzles |
|---|---|
| Just learning multiplication | 5×5 Easy, solved together on paper or screen |
| Confident with times tables | 5×5 Medium and 7×7 Easy |
| Puzzle fans | 7×7 Medium, 10×10 and the Daily Shikaku |
Every child is different — let enjoyment, not age, decide when to move up.
A 45-minute lesson plan
- Warm-up (5 min): “How many different rectangles can you draw with an area of 6?” Draw them on squared paper.
- Rules (5 min): show one 4×4 or 5×5 puzzle on the board and solve the first rectangle together, explaining why.
- Pairs (20 min): pupils solve printed 5×5 puzzles in pairs. Each pair must explain one move to the other.
- Share (10 min): pupils present the “cleverest” deduction they found. Introduce words like forced and only option.
- Exit ticket (5 min): “Why can a 7 only be a straight line?” (Because 7 is prime.)
More activity ideas
- Make your own: pupils draw a grid split into rectangles, write one number in each, and swap with a partner — see how to make a Shikaku.
- Prime hunt: find every prime on a puzzle before solving.
- Daily habit: a class streak on the Daily Shikaku.
Print a classroom set
Up to 12 puzzles per sheet, any size, with an answer key.
Questions
What age is Shikaku suitable for?
Children who are comfortable with small multiplication facts can usually start with 5×5 Easy puzzles. There is no upper limit — large grids challenge adults too.
Is Shikaku educational?
It practises area, factor pairs, logical reasoning and spatial thinking, which is why teachers use it as a maths starter or enrichment activity.
Can children play without an account?
Yes. PuzzleShikaku needs no sign-up, and progress is saved only in the browser.