Q.1
How would you check 45 - 23 = 22?
  • By subtracting 22 from 23
  • By adding 45 and 22
  • By finding the total of all the numbers
  • By adding 23 and 22
Q.2
Use number pairs, or bonds, to 20 to find the incorrect calculation:
  • 20 - 10 = 20
  • 20 - 0 = 20
  • 20 - 15 = 5
  • 20 - 19 = 1
Q.3
If 29 - 15 = 14, what could you do to check the answer?
  • Subtract the numbers in a different order
  • Add 15 and 14 together
  • Take out any harder numbers
  • Put 14 at the beginning of the calculation
Q.4
How do you know that 20 - 10 = 10?
  • Because I know 10 + 10 = 20
  • Because it's a subtraction
  • Because it's an addition
  • Because I know about subtraction
Q.5
Which calculation could you use to check that 16 - 9 = 7 is correct?
  • 16 + 9 = 7
  • 9 + 7 = 16
  • 7 - 16 = 9
  • 7 - 9 = 16
Q.6
If 3 + 4 + 10 + 3 = 20, what could you do to check the answer?
  • Take out all the larger numbers
  • Use multiplication
  • Add some extra numbers in too
  • Add the numbers up again in a different order: 10 + 3 + 3 + 4 or 10 + 4 + 3 + 3
Q.7
Use number pairs, or bonds, to 20 to find the incorrect calculation:
  • 20 - 13 = 7
  • 20 - 8 = 12
  • 20 - 16 = 14
  • 20 - 2 = 18
Q.8
How could you check 62 + 38 = 100?
  • By taking away 100
  • By finding the difference between 62 and 38
  • By subtracting 100 from 62
  • By subtracting 38 from 100
Q.9
Which calculation could you use to check that 15 + 8 = 23 is correct?
  • 23 + 8 = 15
  • 23 + 15 = 8
  • 15 - 8 = 23
  • 23 - 8 = 15
Q.10
What does 'inverse operation' mean?
  • Doing the calculation upside down
  • Making a mistake on purpose
  • The opposite operation
  • A medical procedure
0 h : 0 m : 1 s