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