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 4-digit number.
Discover what number I am by using the following clues:

  1. I am an even number.
  2. I am less than 3000.
  3. All four of my digits are different.
  4. My tens digit is half of my ones digit.
  5. My hundreds digit times my thousands digit is equal to 5.
  6. My ones digit plus my tens digit is equal to my hundreds digit plus my thousands digit.
  7. The product of all four of my digits is equal to 40.
  8. My thousands digit is 4 less than my hundreds digit.
  9. The sum of all four of my digits is equal to 12.

Can you find the mystery number?

Blank spaces for four digits, labelled thousands, hundreds, tens, and ones.

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?

Source: Who Am I? Puzzles – Education Development Center