Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 995 · 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. 1.790 − 119 =
2. 2.916 − 699 =
3. 3.252 − 209 =
4. 4.841 − 127 =
5. 5.723 − 697 =
6. 6.929 − 699 =
7. 7.960 − 549 =
8. 8.834 − 598 =
9. 9.723 − 698 =
10. 10.867 − 527 =
11. 11.952 − 268 =
12. 12.772 − 219 =
13. 13.524 − 397 =
14. 14.597 − 369 =
15. 15.747 − 498 =
16. 16.522 − 377 =
17. 17.393 − 299 =
18. 18.906 − 799 =
19. 19.923 − 397 =
20. 20.776 − 648 =
21. 21.470 − 397 =
22. 22.877 − 697 =
23. 23.578 − 238 =
24. 24.500 − 299 =
25. 25.957 − 799 =
26. 26.948 − 698 =
27. 27.990 − 209 =
28. 28.827 − 497 =
29. 29.320 − 277 =
30. 30.413 − 349 =
31. 31.967 − 497 =
32. 32.598 − 198 =
33. 33.436 − 169 =
34. 34.971 − 429 =
35. 35.935 − 399 =
36. 36.575 − 298 =
37. 37.484 − 197 =
38. 38.993 − 437 =
39. 39.968 − 597 =
40. 40.367 − 197 =

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