Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 531 · 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. 1.758 − 598 =
2. 2.733 − 698 =
3. 3.530 − 439 =
4. 4.634 − 198 =
5. 5.923 − 269 =
6. 6.732 − 469 =
7. 7.399 − 299 =
8. 8.428 − 298 =
9. 9.504 − 299 =
10. 10.714 − 599 =
11. 11.861 − 797 =
12. 12.711 − 589 =
13. 13.572 − 397 =
14. 14.879 − 699 =
15. 15.653 − 398 =
16. 16.904 − 407 =
17. 17.829 − 598 =
18. 18.774 − 697 =
19. 19.851 − 528 =
20. 20.848 − 627 =
21. 21.684 − 177 =
22. 22.841 − 799 =
23. 23.415 − 397 =
24. 24.577 − 277 =
25. 25.870 − 698 =
26. 26.515 − 197 =
27. 27.707 − 649 =
28. 28.990 − 679 =
29. 29.893 − 798 =
30. 30.437 − 297 =
31. 31.832 − 357 =
32. 32.853 − 457 =
33. 33.719 − 697 =
34. 34.910 − 299 =
35. 35.484 − 209 =
36. 36.483 − 457 =
37. 37.392 − 299 =
38. 38.446 − 299 =
39. 39.671 − 598 =
40. 40.532 − 398 =

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