Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 746 · 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 − 247 =
2. 2.890 − 197 =
3. 3.684 − 598 =
4. 4.547 − 397 =
5. 5.589 − 497 =
6. 6.881 − 497 =
7. 7.623 − 319 =
8. 8.425 − 277 =
9. 9.629 − 199 =
10. 10.872 − 697 =
11. 11.316 − 197 =
12. 12.648 − 428 =
13. 13.883 − 799 =
14. 14.965 − 697 =
15. 15.248 − 229 =
16. 16.902 − 418 =
17. 17.952 − 617 =
18. 18.992 − 318 =
19. 19.940 − 799 =
20. 20.888 − 618 =
21. 21.651 − 559 =
22. 22.379 − 199 =
23. 23.973 − 597 =
24. 24.343 − 299 =
25. 25.951 − 299 =
26. 26.825 − 457 =
27. 27.970 − 599 =
28. 28.864 − 798 =
29. 29.639 − 397 =
30. 30.566 − 397 =
31. 31.790 − 298 =
32. 32.818 − 397 =
33. 33.396 − 198 =
34. 34.610 − 499 =
35. 35.901 − 189 =
36. 36.862 − 259 =
37. 37.998 − 398 =
38. 38.633 − 598 =
39. 39.641 − 397 =
40. 40.928 − 567 =

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