Grade
4

Guess My Rule: Mostly Composites

Inside the red circle: 25, 500, 35, 70, 125, and 90. Inside the blue circle: 6, 2, and 3. Inside both circles: 30, 10, and 15. Outside the circles: 12, 4, 17, and 32.
  1. Some numbers belong in the circles, and some do not. What is the rule that decides what belongs in the red circle? What is the rule that decides what belongs in the blue circle? What is the rule to be in both circles?
  2. What is another number that belongs in the intersection of the circles?
  3. What is another number that belongs in only the blue circle?
  4. What is another number that belongs in only the red circle?
  5. What is another number that belongs outside of the circles?

Do the numbers in the red and blue circles have any factors or multiples in common?

  • Make your own rule that uses factors and multiples. You can use the circles below or draw your own.
  • If possible, show some examples that belong inside each circle and some examples that don’t belong in either circle.
blank overlapping circles for your own rules
Printable Version

Google doc for printing and copying

Reference for Educators

Sample problems and solutions