Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 289 · 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. 1.565 − 498 =
2. 2.918 − 599 =
3. 3.837 − 397 =
4. 4.422 − 398 =
5. 5.255 − 188 =
6. 6.772 − 367 =
7. 7.796 − 489 =
8. 8.878 − 499 =
9. 9.405 − 288 =
10. 10.720 − 497 =
11. 11.403 − 148 =
12. 12.884 − 699 =
13. 13.725 − 538 =
14. 14.934 − 297 =
15. 15.668 − 598 =
16. 16.890 − 798 =
17. 17.732 − 428 =
18. 18.856 − 798 =
19. 19.978 − 797 =
20. 20.310 − 198 =
21. 21.928 − 799 =
22. 22.924 − 138 =
23. 23.448 − 367 =
24. 24.911 − 599 =
25. 25.818 − 499 =
26. 26.205 − 159 =
27. 27.364 − 207 =
28. 28.707 − 657 =
29. 29.872 − 597 =
30. 30.990 − 349 =
31. 31.835 − 197 =
32. 32.289 − 199 =
33. 33.639 − 587 =
34. 34.849 − 337 =
35. 35.688 − 497 =
36. 36.877 − 499 =
37. 37.259 − 238 =
38. 38.576 − 237 =
39. 39.291 − 138 =
40. 40.970 − 148 =

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