Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 58 · 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. 1.678 − 259 =
2. 2.539 − 297 =
3. 3.600 − 357 =
4. 4.478 − 299 =
5. 5.333 − 249 =
6. 6.995 − 399 =
7. 7.973 − 248 =
8. 8.648 − 269 =
9. 9.722 − 247 =
10. 10.913 − 608 =
11. 11.479 − 278 =
12. 12.771 − 649 =
13. 13.354 − 249 =
14. 14.815 − 597 =
15. 15.971 − 409 =
16. 16.555 − 199 =
17. 17.735 − 279 =
18. 18.441 − 227 =
19. 19.601 − 497 =
20. 20.888 − 597 =
21. 21.783 − 168 =
22. 22.940 − 489 =
23. 23.904 − 697 =
24. 24.621 − 597 =
25. 25.991 − 797 =
26. 26.684 − 458 =
27. 27.937 − 119 =
28. 28.855 − 797 =
29. 29.612 − 579 =
30. 30.938 − 498 =
31. 31.995 − 368 =
32. 32.942 − 799 =
33. 33.635 − 239 =
34. 34.961 − 599 =
35. 35.865 − 369 =
36. 36.810 − 397 =
37. 37.523 − 149 =
38. 38.921 − 797 =
39. 39.228 − 189 =
40. 40.235 − 149 =

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