Q.1
Which calculation proves this calculation is incorrect? 62 - 19 = 55
  • 55 + 19 = 62
  • 55 + 19 = 74
  • 62 + 19 = 55
  • 62 + 55 = 19
Q.2
Why is 48 - 20 = 54 incorrect?
  • Because 48 is more than 20
  • Because the numbers are all even
  • Because 20 + 54 = 74, not 48
  • Because the total of all three numbers is 122
Q.3
Which calculation could you use to check that 23 - 6 = 17 is correct?
  • 6 + 17
  • 23 + 7
  • 23 + 6 + 7
  • 23 + 6 + 7
Q.4
Check 67 - 25 = 42 with addition. Is this calculation correct?
  • Incorrect answer: 25 + 67 = 92
  • Correct answer: 25 - 67 = 42
  • Incorrect answer: 67 + 42 = 109
  • Correct answer: 25 + 42 = 67
Q.5
Which calculation proves this calculation is incorrect? 76 - 34 = 45
  • 76 - 45 = 34
  • 45 - 34 = 11
  • 34 + 45 = 79
  • 34 + 45 = 76
Q.6
Which calculation could you use to check that 18 - 7 = 11 is correct?
  • 11 + 18
  • 7 + 18
  • 7 + 11
  • 11 + 7 + 18
Q.7
How could you check that 24 - 8 = 16?
  • By checking that 16 + 8 = 24
  • By checking the total of all three numbers
  • By finding the difference between 16 and 8
  • By finding the total of 24 and 8
Q.8
Why is 33 - 20 = 13 true?
  • Because the sum of all three numbers gives the same answer
  • Because 13 subtracted from 20 is 33
  • Because the total of 13 and 33 is 20
  • Because 20 + 13 = 33
Q.9
Check 84 - 21 = 73 with addition. Is this calculation correct?
  • Correct answer: 73 + 21 = 84
  • Incorrect answer: 73 + 21 = 94
  • Incorrect answer: 84 + 21 = 105
  • Incorrect answer: 84 + 73 = 157
Q.10
Which calculation shows that this subtraction is correct? 78 - 40 = 38
  • 40 + 78 = 38
  • 40 - 38 = 78
  • 38 + 78 = 40
  • 38 + 10 + 10 + 10 + 10 = 78
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