Grade 2 · Set D · Side 1 of 2
Why that step is allowed
D
Start Finish
Goal: 15 min for both sides
Score/ 10
Remember: A step is allowed when the amount stays the same.
1Can 85 − 68 become 83 − 70?AllowedNot allowed
working 2Can 72 − 29 become 50 + 7?AllowedNot allowed
working 3Why can 91 − 87 become 94 − 90?Moving some from one number to the other keeps the total.Take a round number, then fix the extra after.Adding the same to both numbers keeps the gap the same.
working 4Can 41 − 18 become 30 + 7?AllowedNot allowed
working 5Can 413 + 497 become 413 + 500 + 3?AllowedNot allowed
working
Grade 2 · Set D · Side 2 of 2
Why that step is allowed
D
Start Finish
Goal: 15 min for both sides
Score/ 10
6Can 57 + 27 become 57 + 30 − 3?AllowedNot allowed
working 7Can 696 + 298 become 696 + 300 + 2?AllowedNot allowed
working 8Can 94 − 78 become 20 + 4?AllowedNot allowed
working 9Can 566 − 496 become 566 − 500 − 4?AllowedNot allowed
working 10Why can 241 + 297 become 241 + 300 − 3?Take a round number, then fix the extra after.Moving some from one number to the other keeps the total.Adding the same to both numbers keeps the gap the same.
working Answer key · Grade 2 · Set D
Why that step is allowed
1Not allowed
2Not allowed
3Adding the same to both numbers keeps the gap the same.
4Not allowed
5Not allowed
6Allowed
7Not allowed
8Not allowed
9Not allowed
10Take a round number, then fix the extra after.
Mark each answer, count the right ones and write the score on the sheet. Beat your own time next time.