Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 44 · 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. 1.935 − 198 =
2. 2.988 − 118 =
3. 3.563 − 428 =
4. 4.605 − 127 =
5. 5.630 − 599 =
6. 6.637 − 328 =
7. 7.961 − 598 =
8. 8.761 − 698 =
9. 9.884 − 698 =
10. 10.613 − 359 =
11. 11.517 − 397 =
12. 12.402 − 307 =
13. 13.525 − 457 =
14. 14.572 − 198 =
15. 15.645 − 227 =
16. 16.954 − 299 =
17. 17.708 − 317 =
18. 18.623 − 497 =
19. 19.648 − 549 =
20. 20.640 − 499 =
21. 21.826 − 799 =
22. 22.760 − 459 =
23. 23.404 − 299 =
24. 24.949 − 197 =
25. 25.820 − 167 =
26. 26.689 − 498 =
27. 27.902 − 128 =
28. 28.894 − 488 =
29. 29.840 − 499 =
30. 30.838 − 398 =
31. 31.882 − 399 =
32. 32.994 − 398 =
33. 33.920 − 799 =
34. 34.980 − 238 =
35. 35.737 − 397 =
36. 36.665 − 147 =
37. 37.410 − 298 =
38. 38.339 − 259 =
39. 39.922 − 698 =
40. 40.385 − 198 =

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