Puzzles and Riddles

Learning Goals:

  • Build a deeper understanding of the multiplication operation
  • Solve problems involving the multiplication of one-digit whole numbers
  • Communicate mathematical thinking orally and visually

The Challenge:

For each of the regions marked A to H below, think of a number that could belong in it.

Reminder: A factor of a number is a number that divides into that number with no remainder.

For example, 10 could fit in A, the “multiple of 5” region, but actually needs to go in the D region, as it is also a factor of 40 (but is not also a multiple of 4.)

Questions and Prompts to Support your Child:

  • Which section did you start thinking about first? Why did you choose that section first?
  • Which sections do you think have the least possibilities? Why?
  • (Once a number has been found for each section) Do you think there are any other numbers that could fit as well?

Extensions & Adaptations:

  • If you’re feeling stuck, try starting with the G section in the middle (find a number that is a factor of 40, as well as being a multiple of both 4 and 5)
  • Once you have found one possible set of numbers, take some time to find other possibilities – 5 numbers for each section would be a good goal!

Source: The Guardian – Alex Bellos’ Monday Puzzle