Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 695 · 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. 1.818 − 247 =
2. 2.763 − 697 =
3. 3.953 − 548 =
4. 4.462 − 408 =
5. 5.364 − 299 =
6. 6.733 − 597 =
7. 7.901 − 647 =
8. 8.861 − 399 =
9. 9.654 − 398 =
10. 10.303 − 197 =
11. 11.880 − 799 =
12. 12.796 − 458 =
13. 13.733 − 198 =
14. 14.709 − 407 =
15. 15.429 − 369 =
16. 16.797 − 599 =
17. 17.888 − 499 =
18. 18.244 − 199 =
19. 19.482 − 417 =
20. 20.799 − 399 =
21. 21.434 − 398 =
22. 22.319 − 269 =
23. 23.572 − 399 =
24. 24.476 − 417 =
25. 25.455 − 219 =
26. 26.794 − 438 =
27. 27.840 − 197 =
28. 28.582 − 487 =
29. 29.969 − 698 =
30. 30.360 − 277 =
31. 31.807 − 597 =
32. 32.797 − 248 =
33. 33.355 − 239 =
34. 34.780 − 297 =
35. 35.826 − 397 =
36. 36.577 − 397 =
37. 37.652 − 117 =
38. 38.800 − 559 =
39. 39.803 − 618 =
40. 40.921 − 487 =

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