Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 946 · 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. 1.445 − 297 =
2. 2.877 − 798 =
3. 3.305 − 118 =
4. 4.853 − 799 =
5. 5.843 − 799 =
6. 6.823 − 298 =
7. 7.958 − 198 =
8. 8.845 − 669 =
9. 9.584 − 469 =
10. 10.328 − 257 =
11. 11.807 − 677 =
12. 12.687 − 439 =
13. 13.880 − 498 =
14. 14.545 − 199 =
15. 15.934 − 419 =
16. 16.549 − 398 =
17. 17.612 − 288 =
18. 18.549 − 428 =
19. 19.762 − 159 =
20. 20.314 − 298 =
21. 21.964 − 797 =
22. 22.540 − 399 =
23. 23.981 − 597 =
24. 24.658 − 498 =
25. 25.751 − 679 =
26. 26.889 − 299 =
27. 27.465 − 397 =
28. 28.937 − 199 =
29. 29.942 − 699 =
30. 30.873 − 498 =
31. 31.402 − 297 =
32. 32.799 − 698 =
33. 33.648 − 299 =
34. 34.728 − 258 =
35. 35.415 − 328 =
36. 36.873 − 169 =
37. 37.852 − 398 =
38. 38.552 − 278 =
39. 39.350 − 238 =
40. 40.438 − 297 =

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