Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 621 · 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. 1.833 − 397 =
2. 2.804 − 398 =
3. 3.674 − 529 =
4. 4.976 − 359 =
5. 5.417 − 187 =
6. 6.585 − 498 =
7. 7.672 − 598 =
8. 8.727 − 678 =
9. 9.628 − 498 =
10. 10.972 − 499 =
11. 11.982 − 597 =
12. 12.666 − 407 =
13. 13.335 − 298 =
14. 14.916 − 589 =
15. 15.767 − 629 =
16. 16.287 − 267 =
17. 17.406 − 367 =
18. 18.544 − 398 =
19. 19.651 − 399 =
20. 20.978 − 497 =
21. 21.544 − 297 =
22. 22.374 − 247 =
23. 23.976 − 797 =
24. 24.623 − 209 =
25. 25.936 − 698 =
26. 26.704 − 598 =
27. 27.805 − 599 =
28. 28.429 − 118 =
29. 29.475 − 197 =
30. 30.766 − 387 =
31. 31.590 − 388 =
32. 32.391 − 209 =
33. 33.466 − 277 =
34. 34.902 − 598 =
35. 35.779 − 479 =
36. 36.816 − 608 =
37. 37.809 − 697 =
38. 38.731 − 198 =
39. 39.977 − 619 =
40. 40.390 − 319 =

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