Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 208 · 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. 1.940 − 797 =
2. 2.822 − 627 =
3. 3.591 − 567 =
4. 4.855 − 578 =
5. 5.963 − 399 =
6. 6.794 − 297 =
7. 7.701 − 579 =
8. 8.967 − 317 =
9. 9.457 − 408 =
10. 10.869 − 199 =
11. 11.706 − 349 =
12. 12.872 − 499 =
13. 13.962 − 798 =
14. 14.547 − 498 =
15. 15.478 − 199 =
16. 16.553 − 498 =
17. 17.860 − 128 =
18. 18.664 − 267 =
19. 19.966 − 199 =
20. 20.914 − 699 =
21. 21.757 − 278 =
22. 22.720 − 207 =
23. 23.997 − 799 =
24. 24.632 − 257 =
25. 25.839 − 488 =
26. 26.897 − 539 =
27. 27.651 − 617 =
28. 28.818 − 197 =
29. 29.630 − 297 =
30. 30.967 − 679 =
31. 31.606 − 497 =
32. 32.570 − 298 =
33. 33.909 − 498 =
34. 34.950 − 598 =
35. 35.713 − 198 =
36. 36.651 − 498 =
37. 37.576 − 517 =
38. 38.745 − 299 =
39. 39.955 − 267 =
40. 40.561 − 177 =

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