Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 574 · 40 questions

How to do it in your head (Round up, add back): Round the number you take away up to the next ten or hundred: 297 → 300 (3 too many). Take away the round number. Add back the extra, because you took away too much.

1. 1.707 − 598 =
2. 2.964 − 538 =
3. 3.808 − 698 =
4. 4.660 − 397 =
5. 5.609 − 558 =
6. 6.857 − 667 =
7. 7.397 − 337 =
8. 8.688 − 617 =
9. 9.768 − 698 =
10. 10.576 − 468 =
11. 11.449 − 299 =
12. 12.936 − 797 =
13. 13.768 − 429 =
14. 14.838 − 527 =
15. 15.569 − 308 =
16. 16.553 − 378 =
17. 17.461 − 288 =
18. 18.411 − 297 =
19. 19.852 − 599 =
20. 20.634 − 599 =
21. 21.921 − 619 =
22. 22.531 − 449 =
23. 23.695 − 299 =
24. 24.939 − 688 =
25. 25.702 − 599 =
26. 26.962 − 418 =
27. 27.699 − 619 =
28. 28.573 − 199 =
29. 29.870 − 448 =
30. 30.508 − 458 =
31. 31.588 − 358 =
32. 32.862 − 159 =
33. 33.388 − 198 =
34. 34.757 − 517 =
35. 35.816 − 797 =
36. 36.878 − 197 =
37. 37.686 − 299 =
38. 38.342 − 278 =
39. 39.674 − 469 =
40. 40.612 − 269 =

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