Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 319 · 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. 1.250 − 218 =
2. 2.768 − 577 =
3. 3.981 − 197 =
4. 4.590 − 499 =
5. 5.314 − 297 =
6. 6.794 − 499 =
7. 7.485 − 198 =
8. 8.313 − 297 =
9. 9.573 − 297 =
10. 10.555 − 208 =
11. 11.725 − 699 =
12. 12.920 − 568 =
13. 13.711 − 297 =
14. 14.767 − 497 =
15. 15.926 − 337 =
16. 16.982 − 487 =
17. 17.633 − 339 =
18. 18.196 − 147 =
19. 19.434 − 298 =
20. 20.700 − 198 =
21. 21.636 − 397 =
22. 22.918 − 438 =
23. 23.298 − 219 =
24. 24.367 − 299 =
25. 25.943 − 557 =
26. 26.628 − 467 =
27. 27.857 − 799 =
28. 28.798 − 298 =
29. 29.923 − 797 =
30. 30.709 − 599 =
31. 31.575 − 267 =
32. 32.955 − 538 =
33. 33.844 − 388 =
34. 34.420 − 268 =
35. 35.613 − 539 =
36. 36.964 − 638 =
37. 37.611 − 498 =
38. 38.477 − 159 =
39. 39.329 − 299 =
40. 40.787 − 497 =

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