Say: “Every row (going across) needs to have ALL of the shapes in. AND every column (going down) too.”
Draw: One of the grids below (don’t worry about using colour.)
Starter
“Which shape is missing?”
Main
“Which shapes are missing?”
Dessert
“Fill in the blank boxes”
Tips for grown-ups
Don’t rush to correct mistakes. Ask them to explain their answer - you can say “Ok!” and move on.
Discussing the puzzles is more important than getting the right answer - they will keep thinking about them, and even revise their answer days later!
Dessert has more than one answer (four, in fact). Stretch question: “How many different answers can you find?”
Branch of mathematics
Combinatorics and logic. A grid where every shape appears once in each row and column is called a Latin square. Mathematicians have studied them since the 1700s, and they are the idea behind sudoku.
Answers
Starter: the empty box is a circle.
Main: there is only one way to finish it. Top row: circle, triangle, square. Middle row: triangle, square, circle. Bottom row: square, circle, triangle.
Dessert: four ways. Once the top row is chosen (triangle then circle then square, or triangle then square then circle), there are two ways to finish the rest.
How did it go at your table? Let me know in the comments!