Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 616 · 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. 1.796 − 187 =
2. 2.759 − 577 =
3. 3.361 − 237 =
4. 4.609 − 369 =
5. 5.935 − 698 =
6. 6.645 − 339 =
7. 7.805 − 599 =
8. 8.982 − 398 =
9. 9.438 − 347 =
10. 10.301 − 267 =
11. 11.530 − 297 =
12. 12.554 − 537 =
13. 13.779 − 298 =
14. 14.303 − 197 =
15. 15.550 − 397 =
16. 16.522 − 409 =
17. 17.826 − 199 =
18. 18.665 − 599 =
19. 19.936 − 438 =
20. 20.731 − 698 =
21. 21.698 − 298 =
22. 22.919 − 547 =
23. 23.335 − 198 =
24. 24.690 − 377 =
25. 25.961 − 207 =
26. 26.977 − 798 =
27. 27.645 − 597 =
28. 28.632 − 278 =
29. 29.451 − 198 =
30. 30.797 − 698 =
31. 31.909 − 799 =
32. 32.993 − 298 =
33. 33.619 − 399 =
34. 34.444 − 199 =
35. 35.914 − 598 =
36. 36.225 − 167 =
37. 37.870 − 797 =
38. 38.638 − 599 =
39. 39.586 − 479 =
40. 40.557 − 268 =

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