Puzzles and Riddles

Digits from 0 to 9 piled together.

Learning Goals:

  • Determine the missing numbers in equations
  • Develop and apply reasoning skills to make and test math predictions
  • Communicate mathematical thinking orally and visually

The Challenge:

I am a mystery number between 0 and 100.

Discover what number I am by using the following clues:

  1. I am more than 25.
  2. My ones digit is even.
  3. My tenths digit is even.
  4. The product of all three of my digits multiplied together is 24.
  5. My tenths digit is half of my ones digit.
  6. My tens digit times my tenths digit is equal to 6.
  7. My tens digit is odd.
  8. My ones digit is my highest digit.
  9. The sum of my digits is 9.

Can you find the mystery number?

Blank spaces for three digits, labelled tens, ones, and tenths.

Questions and Prompts to Support your Child:

  • Which clue did you start with? Why did you use that one first?
  • Which clue narrowed things down the most? Which was the least specific?

Extensions & Adaptations:

  • Create a set of clues that will lead someone to a different decimal number. How can you be sure that your clues will lead them to only one possible solution?
  • Try out some more ‘Who am I’ puzzles here!

Source: Who Am I? Puzzles – Education Development Center