Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 784 · 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. 1.926 − 499 =
2. 2.638 − 297 =
3. 3.778 − 129 =
4. 4.855 − 698 =
5. 5.664 − 478 =
6. 6.348 − 297 =
7. 7.738 − 398 =
8. 8.928 − 797 =
9. 9.976 − 799 =
10. 10.488 − 299 =
11. 11.654 − 498 =
12. 12.931 − 798 =
13. 13.584 − 259 =
14. 14.935 − 668 =
15. 15.998 − 599 =
16. 16.771 − 498 =
17. 17.743 − 149 =
18. 18.622 − 607 =
19. 19.312 − 219 =
20. 20.373 − 299 =
21. 21.564 − 199 =
22. 22.735 − 697 =
23. 23.907 − 679 =
24. 24.668 − 217 =
25. 25.539 − 497 =
26. 26.463 − 297 =
27. 27.922 − 698 =
28. 28.821 − 147 =
29. 29.902 − 599 =
30. 30.931 − 399 =
31. 31.482 − 269 =
32. 32.400 − 237 =
33. 33.720 − 497 =
34. 34.832 − 397 =
35. 35.868 − 158 =
36. 36.683 − 197 =
37. 37.469 − 298 =
38. 38.787 − 538 =
39. 39.734 − 367 =
40. 40.480 − 158 =

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