Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 429 · 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. 1.641 − 119 =
2. 2.891 − 698 =
3. 3.350 − 299 =
4. 4.465 − 308 =
5. 5.825 − 799 =
6. 6.518 − 267 =
7. 7.840 − 627 =
8. 8.429 − 398 =
9. 9.692 − 657 =
10. 10.514 − 397 =
11. 11.885 − 797 =
12. 12.588 − 399 =
13. 13.750 − 699 =
14. 14.488 − 299 =
15. 15.946 − 637 =
16. 16.716 − 419 =
17. 17.758 − 208 =
18. 18.934 − 627 =
19. 19.897 − 799 =
20. 20.786 − 647 =
21. 21.229 − 209 =
22. 22.918 − 459 =
23. 23.827 − 798 =
24. 24.724 − 197 =
25. 25.572 − 447 =
26. 26.830 − 399 =
27. 27.345 − 197 =
28. 28.257 − 198 =
29. 29.640 − 369 =
30. 30.989 − 597 =
31. 31.828 − 599 =
32. 32.781 − 468 =
33. 33.994 − 607 =
34. 34.950 − 399 =
35. 35.949 − 799 =
36. 36.874 − 497 =
37. 37.904 − 649 =
38. 38.981 − 447 =
39. 39.954 − 647 =
40. 40.939 − 599 =

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