Grade
4

Guess My Rule: Multiplication

A Venn diagram with a red circle and a blue circle. Expressions in the red circle. 18 times 19. 12 times 12. 13 times 15. 133 times 3. 20 times 20. And 23 times 15. Expressions in the blue circle. 42 times 13. 26 times 20. 32 times 25. 22 times 24. And 43 times 14. Expressions in both circles. 6 times 83. 20 times 21. 23 times 18. 15 times 33. And 67 times 6.
  1. Some expressions belong in the circle, and some do not. What is the rule to be in the red circle? What is the rule to be in the blue circle? What is the rule to be in both circles?
  2. Can you write an expression that would go inside the intersection of the circles? How do you know?
  3. Write another expression that belongs in only the red circle.
  4. Write another expression that belongs in only the blue circle.
  • Find the products of each expression.
  • What do you notice about the products of the expressions in the middle?
  • What do you think that means about the rules for the red and blue circles?

Make your own rule, using expressions. 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.

An empty Venn diagram. The rule for the red circle is blank. The rule for the blue circle is blank.
Printable Version

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Reference for Educators

Sample problems and solutions