Section A: True or False?

WALT: We are learning to decide whether equations are true or false and explain our thinking.

Remember: An equation is a number sentence that compares two amounts. The equals sign = means “has the same value as”. Check both sides of the equation.

Success criteria: I can read <, > and = correctly. I can check both sides. I can explain how I know.

Circle True or False. Show your working when you need to.

1. 7 + 3 = 12

True

False

2. 14 - 6 = 9

True

False

3. 20 + 5 < 30

True

False

4. 18 - 8 = 10

True

False

5. 6 = 2 + 4

True

False

6. 15 = 23 - 7

True

False

7. 9 + 8 = 20 - 3

True

False

8. 36 - 16 = 20

True

False

9. 40 - 12 = 31

True

False

10. 25 + 17 = 50 - 8

True

False

Section B: Find the Missing Number

Write the missing number in each open number sentence. Use a number line, counters or another strategy if helpful.

11. 8 + □ = 15

12. □ + 36 = 80

13. 24 - □ = 9

14. □ - 18 = 27

15. 420 - □ = 401

16. □ + 125 = 300

17. 53 - □ = 40

18. 67 = 40 + □

Section C: Prove It

Explain or show how you know. You may use numbers, words, a drawing or materials.

19. Is 28 + 14 = 50 - 8 true or false? Prove it.

20. Is 63 - 27 = 35 true or false? Prove it.

21. A classmate says 36 = 20 + 16 is false because the answer should come after the equals sign. What would you say?

22. Complete and explain: 45 - □ = 30

Challenge

Use the same numbers 36, 20 and 16 to create one true equation and one false equation. Use +, - and =. Explain how you checked them.

Teacher Answer Key

Section A: 1 False, 2 False, 3 True, 4 True, 5 True, 6 False, 7 True, 8 True, 9 False, 10 True.

Section B: 11 = 7, 12 = 44, 13 = 15, 14 = 45, 15 = 19, 16 = 175, 17 = 13, 18 = 27.

Section C: 19 True: both sides equal 42. 20 False: 63 - 27 = 36, not 35. 21 The equals sign means both sides have the same value; 20 + 16 = 36, so the equation is true. 22 □ = 15; 45 - 15 = 30.

Challenge: Answers will vary. Example true equation: 36 = 20 + 16. Example false equation: 36 - 20 = 16 is true, so students must alter it to make it false, such as 36 - 16 = 20 + 1.