Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 730 · 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. 1.567 − 339 =
2. 2.788 − 627 =
3. 3.436 − 399 =
4. 4.231 − 168 =
5. 5.434 − 299 =
6. 6.620 − 568 =
7. 7.959 − 608 =
8. 8.629 − 477 =
9. 9.962 − 259 =
10. 10.780 − 208 =
11. 11.342 − 198 =
12. 12.530 − 299 =
13. 13.693 − 497 =
14. 14.716 − 698 =
15. 15.808 − 589 =
16. 16.918 − 799 =
17. 17.879 − 138 =
18. 18.779 − 398 =
19. 19.372 − 299 =
20. 20.748 − 669 =
21. 21.550 − 187 =
22. 22.504 − 419 =
23. 23.843 − 649 =
24. 24.741 − 398 =
25. 25.549 − 498 =
26. 26.650 − 497 =
27. 27.990 − 697 =
28. 28.965 − 599 =
29. 29.770 − 447 =
30. 30.907 − 699 =
31. 31.855 − 297 =
32. 32.769 − 698 =
33. 33.564 − 197 =
34. 34.775 − 597 =
35. 35.670 − 299 =
36. 36.793 − 697 =
37. 37.440 − 239 =
38. 38.706 − 298 =
39. 39.951 − 349 =
40. 40.800 − 267 =

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