Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 559 · 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. 1.989 − 398 =
2. 2.327 − 249 =
3. 3.969 − 698 =
4. 4.633 − 498 =
5. 5.246 − 197 =
6. 6.800 − 499 =
7. 7.928 − 497 =
8. 8.851 − 199 =
9. 9.939 − 399 =
10. 10.682 − 638 =
11. 11.959 − 557 =
12. 12.984 − 697 =
13. 13.878 − 798 =
14. 14.662 − 197 =
15. 15.582 − 498 =
16. 16.259 − 177 =
17. 17.914 − 798 =
18. 18.639 − 298 =
19. 19.663 − 648 =
20. 20.914 − 599 =
21. 21.367 − 197 =
22. 22.874 − 799 =
23. 23.746 − 549 =
24. 24.860 − 417 =
25. 25.687 − 269 =
26. 26.920 − 597 =
27. 27.873 − 387 =
28. 28.658 − 598 =
29. 29.774 − 197 =
30. 30.233 − 198 =
31. 31.697 − 598 =
32. 32.999 − 797 =
33. 33.902 − 397 =
34. 34.948 − 497 =
35. 35.678 − 127 =
36. 36.522 − 399 =
37. 37.669 − 599 =
38. 38.796 − 197 =
39. 39.716 − 597 =
40. 40.369 − 288 =

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