Grade
3

Guess My Rule: Multi-Digit Operations

Inside the red circle: 262 + 10. 172 + 100. 252 + 20. 5 + 267, and 12 + 260. Inside the blue circle: 248 − 16. 465 − 53. 365 − 43. 562 − 30, and 535 − 203. Inside both circles: 292 − 20. 282 − 10, and 274 − 2. Outside of the circles: 235 + 20. 485 − 50. 345 + 50. 365 − 45. 359 + 40, and 133 + 30.
  1. Some numbers belong in the circles, and some do not.
    What is the rule to decide what belongs in the red circle?
    What is the rule to decide what belongs in the blue circle?
    What is the rule to decide what belongs in both circles?
  2. Write at least one more expression that belongs only in the red circle.
  3. Write at least one more expression that belongs only in the blue circle.
  4. Write at least one more expression that belongs in the intersection of the two circles.
  • What do you notice about the operations?
  • What do you notice about the sums and differences?

Make your own rules about adding or subtracting. 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