Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 601 · 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. 1.705 − 299 =
2. 2.854 − 797 =
3. 3.995 − 797 =
4. 4.792 − 678 =
5. 5.744 − 699 =
6. 6.511 − 468 =
7. 7.564 − 477 =
8. 8.684 − 297 =
9. 9.978 − 399 =
10. 10.896 − 219 =
11. 11.772 − 697 =
12. 12.890 − 408 =
13. 13.478 − 297 =
14. 14.295 − 227 =
15. 15.557 − 429 =
16. 16.402 − 377 =
17. 17.947 − 198 =
18. 18.391 − 297 =
19. 19.934 − 197 =
20. 20.686 − 298 =
21. 21.476 − 299 =
22. 22.938 − 798 =
23. 23.766 − 199 =
24. 24.666 − 457 =
25. 25.965 − 399 =
26. 26.760 − 399 =
27. 27.725 − 528 =
28. 28.990 − 689 =
29. 29.876 − 388 =
30. 30.552 − 519 =
31. 31.843 − 699 =
32. 32.781 − 697 =
33. 33.279 − 219 =
34. 34.854 − 657 =
35. 35.366 − 259 =
36. 36.431 − 398 =
37. 37.888 − 598 =
38. 38.599 − 217 =
39. 39.930 − 797 =
40. 40.896 − 119 =

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