Puzzles and Riddles

Learning Goals:

  • Determine the missing numbers in equations
  • Develop and apply reasoning skills to make and test math predictions

The Exploration:

The goal of windmill puzzle is to place the numbers from 1-9 in the circles, so that each coloured triangle adds up to the same total:

A collection of nine blank circles, organized into three triangles, one circle for each corner. There is a green triangle in the top left, a blue triangle in the top right, and a red triangle at the bottom. One circle from each of these forms the centre yellow triangle in the middle of the puzzle. The digits from 1-9 are listed underneath.

Can you place the numbers 1-9 into the circles so that each of the coloured triangles adds to 15?

Questions and Prompts to Support your Child:

  • What have you tried so far? What could we try together?
  • If that arrangement of numbers didn’t work out, what could you try instead?
  • What combinations of three digits add to 15? Which have you tried?

Extensions & Adaptations:

  • If you’re feeling stuck, focus on trying different numbers in the middle triangle – those digits are more important than the rest
  • What other target totals are possible? What target totals are impossible? You could try using a different set of digits for in the spaces, or try using a number more than once. How do these changes affect the puzzle?

Source: Don Steward Blog