Grade 2 · Set E · Side 1 of 2
Why that step is allowed
E
Start Finish
Goal: 15 min for both sides
Score/ 10
Remember: A step is allowed when the amount stays the same.
1Why can 194 + 375 become 375 + 194?Take a round number, then fix the extra after.Each number splits into its tens and its ones.You can add numbers in any order.
working 2Can 752 − 696 become 752 − 700 + 4?AllowedNot allowed
working 3Why can 411 + 481 become 481 + 411?Take a round number, then fix the extra after.Each number splits into its tens and its ones.You can add numbers in any order.
working 4Why can 478 + 496 become 478 + 500 − 4?Adding the same to both numbers keeps the gap the same.Moving some from one number to the other keeps the total.Take a round number, then fix the extra after.
working 5Why can 233 − 196 become 237 − 200?Moving some from one number to the other keeps the total.Adding the same to both numbers keeps the gap the same.Take a round number, then fix the extra after.
working
Grade 2 · Set E · Side 2 of 2
Why that step is allowed
E
Start Finish
Goal: 15 min for both sides
Score/ 10
6Why can 336 + 385 become 385 + 336?You can add numbers in any order.Take a round number, then fix the extra after.Each number splits into its tens and its ones.
working 7Can 264 + 197 become 264 + 200 + 3?AllowedNot allowed
working 8Can 824 − 198 become 824 − 200 + 2?AllowedNot allowed
working 9Can 488 + 398 become 486 + 400?AllowedNot allowed
working 10Can 392 + 597 become 392 + 600 − 3?AllowedNot allowed
working Answer key · Grade 2 · Set E
Why that step is allowed
1You can add numbers in any order.
2Allowed
3You can add numbers in any order.
4Take a round number, then fix the extra after.
5Adding the same to both numbers keeps the gap the same.
6You can add numbers in any order.
7Not allowed
8Allowed
9Allowed
10Allowed
Mark each answer, count the right ones and write the score on the sheet. Beat your own time next time.