Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 40 · 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. 1.679 − 599 =
2. 2.578 − 327 =
3. 3.725 − 437 =
4. 4.774 − 697 =
5. 5.485 − 448 =
6. 6.857 − 557 =
7. 7.926 − 298 =
8. 8.962 − 657 =
9. 9.877 − 478 =
10. 10.329 − 209 =
11. 11.589 − 228 =
12. 12.767 − 199 =
13. 13.849 − 548 =
14. 14.543 − 498 =
15. 15.416 − 399 =
16. 16.584 − 377 =
17. 17.960 − 498 =
18. 18.909 − 398 =
19. 19.728 − 169 =
20. 20.869 − 499 =
21. 21.738 − 577 =
22. 22.840 − 799 =
23. 23.813 − 599 =
24. 24.998 − 797 =
25. 25.295 − 249 =
26. 26.339 − 199 =
27. 27.507 − 298 =
28. 28.679 − 588 =
29. 29.422 − 189 =
30. 30.841 − 397 =
31. 31.719 − 277 =
32. 32.337 − 298 =
33. 33.847 − 799 =
34. 34.568 − 488 =
35. 35.854 − 798 =
36. 36.757 − 397 =
37. 37.271 − 117 =
38. 38.858 − 578 =
39. 39.560 − 397 =
40. 40.679 − 437 =

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