Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 260 · 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. 1.811 − 697 =
2. 2.583 − 198 =
3. 3.337 − 237 =
4. 4.766 − 199 =
5. 5.684 − 507 =
6. 6.808 − 198 =
7. 7.496 − 309 =
8. 8.461 − 397 =
9. 9.517 − 299 =
10. 10.693 − 138 =
11. 11.826 − 697 =
12. 12.295 − 207 =
13. 13.909 − 609 =
14. 14.764 − 498 =
15. 15.669 − 399 =
16. 16.946 − 648 =
17. 17.836 − 668 =
18. 18.830 − 627 =
19. 19.533 − 498 =
20. 20.805 − 199 =
21. 21.536 − 188 =
22. 22.742 − 338 =
23. 23.592 − 169 =
24. 24.916 − 297 =
25. 25.460 − 197 =
26. 26.443 − 299 =
27. 27.925 − 449 =
28. 28.390 − 337 =
29. 29.833 − 568 =
30. 30.768 − 669 =
31. 31.737 − 369 =
32. 32.648 − 399 =
33. 33.844 − 637 =
34. 34.563 − 157 =
35. 35.443 − 249 =
36. 36.843 − 199 =
37. 37.424 − 199 =
38. 38.831 − 257 =
39. 39.914 − 488 =
40. 40.624 − 489 =

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