Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 306 · 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. 1.880 − 599 =
2. 2.350 − 207 =
3. 3.790 − 397 =
4. 4.847 − 667 =
5. 5.300 − 199 =
6. 6.633 − 449 =
7. 7.846 − 327 =
8. 8.927 − 148 =
9. 9.518 − 238 =
10. 10.929 − 797 =
11. 11.562 − 198 =
12. 12.835 − 497 =
13. 13.747 − 297 =
14. 14.772 − 559 =
15. 15.395 − 299 =
16. 16.940 − 697 =
17. 17.598 − 469 =
18. 18.717 − 147 =
19. 19.852 − 647 =
20. 20.875 − 597 =
21. 21.580 − 327 =
22. 22.735 − 239 =
23. 23.817 − 429 =
24. 24.348 − 207 =
25. 25.686 − 328 =
26. 26.465 − 177 =
27. 27.957 − 459 =
28. 28.325 − 309 =
29. 29.368 − 208 =
30. 30.873 − 198 =
31. 31.434 − 377 =
32. 32.735 − 598 =
33. 33.987 − 557 =
34. 34.999 − 497 =
35. 35.964 − 698 =
36. 36.637 − 599 =
37. 37.741 − 599 =
38. 38.386 − 199 =
39. 39.595 − 459 =
40. 40.655 − 628 =

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