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

  1. I am less than 70.
  2. I am greater than 35.
  3. The sum of my digits is equal to ten.
  4. My ones digit times my tenths digit equals 6.
  5. The product of all three of my digits is 30.
  6. My ones digit is greater than my tenths digit.
  7. My tenths digit + my ones digit = my tens digit.

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?

Source: Who Am I? Puzzles – Education Development Center