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 10.
Discover what number I am by using the following clues:

  1. I am less than 9.
  2. All of my digits are different.
  3. All of my digits are odd.
  4. The sum of all my digits is 15.
  5. My ones digit is greater than my tenths digit.
  6. My tenths digit is greater than my hundredths digit.
  7. My hundredths digit is greater than 1.
  8. The product of my tenths digit times my hundredths digit is 15.

Can you find the mystery number?

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

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