Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 314 · 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. 1.401 − 299 =
2. 2.459 − 239 =
3. 3.568 − 498 =
4. 4.927 − 469 =
5. 5.579 − 199 =
6. 6.698 − 628 =
7. 7.705 − 499 =
8. 8.716 − 599 =
9. 9.883 − 199 =
10. 10.755 − 548 =
11. 11.339 − 298 =
12. 12.498 − 258 =
13. 13.838 − 579 =
14. 14.499 − 187 =
15. 15.767 − 399 =
16. 16.744 − 547 =
17. 17.623 − 499 =
18. 18.735 − 218 =
19. 19.985 − 197 =
20. 20.681 − 598 =
21. 21.405 − 198 =
22. 22.442 − 197 =
23. 23.801 − 178 =
24. 24.799 − 697 =
25. 25.562 − 249 =
26. 26.719 − 348 =
27. 27.813 − 499 =
28. 28.787 − 599 =
29. 29.711 − 647 =
30. 30.306 − 117 =
31. 31.616 − 498 =
32. 32.952 − 547 =
33. 33.942 − 799 =
34. 34.639 − 117 =
35. 35.955 − 797 =
36. 36.975 − 197 =
37. 37.975 − 617 =
38. 38.741 − 168 =
39. 39.678 − 498 =
40. 40.421 − 369 =

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