Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 480 · 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. 1.464 − 398 =
2. 2.646 − 378 =
3. 3.860 − 698 =
4. 4.459 − 219 =
5. 5.514 − 417 =
6. 6.441 − 397 =
7. 7.993 − 799 =
8. 8.328 − 298 =
9. 9.503 − 358 =
10. 10.954 − 698 =
11. 11.251 − 129 =
12. 12.659 − 498 =
13. 13.741 − 679 =
14. 14.967 − 797 =
15. 15.802 − 698 =
16. 16.450 − 408 =
17. 17.854 − 258 =
18. 18.719 − 527 =
19. 19.949 − 688 =
20. 20.447 − 167 =
21. 21.881 − 799 =
22. 22.488 − 387 =
23. 23.967 − 298 =
24. 24.763 − 647 =
25. 25.959 − 419 =
26. 26.851 − 338 =
27. 27.338 − 198 =
28. 28.827 − 479 =
29. 29.889 − 499 =
30. 30.865 − 508 =
31. 31.812 − 799 =
32. 32.352 − 197 =
33. 33.758 − 399 =
34. 34.786 − 598 =
35. 35.758 − 619 =
36. 36.940 − 469 =
37. 37.543 − 387 =
38. 38.565 − 549 =
39. 39.534 − 458 =
40. 40.901 − 599 =

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