Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 36 · 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. 1.877 − 479 =
2. 2.325 − 188 =
3. 3.637 − 398 =
4. 4.275 − 198 =
5. 5.376 − 159 =
6. 6.822 − 519 =
7. 7.789 − 697 =
8. 8.857 − 498 =
9. 9.925 − 489 =
10. 10.971 − 598 =
11. 11.665 − 409 =
12. 12.218 − 198 =
13. 13.661 − 497 =
14. 14.587 − 249 =
15. 15.716 − 379 =
16. 16.695 − 468 =
17. 17.447 − 167 =
18. 18.808 − 298 =
19. 19.967 − 497 =
20. 20.987 − 567 =
21. 21.418 − 357 =
22. 22.833 − 397 =
23. 23.979 − 797 =
24. 24.953 − 267 =
25. 25.710 − 499 =
26. 26.923 − 669 =
27. 27.654 − 598 =
28. 28.516 − 197 =
29. 29.555 − 297 =
30. 30.317 − 199 =
31. 31.486 − 369 =
32. 32.830 − 797 =
33. 33.529 − 299 =
34. 34.678 − 398 =
35. 35.478 − 137 =
36. 36.626 − 498 =
37. 37.891 − 239 =
38. 38.768 − 297 =
39. 39.832 − 637 =
40. 40.864 − 528 =

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