Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 291 · 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. 1.875 − 798 =
2. 2.992 − 699 =
3. 3.456 − 297 =
4. 4.567 − 357 =
5. 5.411 − 279 =
6. 6.831 − 797 =
7. 7.515 − 397 =
8. 8.493 − 299 =
9. 9.958 − 398 =
10. 10.740 − 617 =
11. 11.874 − 699 =
12. 12.689 − 599 =
13. 13.745 − 188 =
14. 14.863 − 399 =
15. 15.768 − 427 =
16. 16.624 − 488 =
17. 17.530 − 397 =
18. 18.607 − 338 =
19. 19.859 − 798 =
20. 20.822 − 799 =
21. 21.914 − 409 =
22. 22.985 − 697 =
23. 23.569 − 379 =
24. 24.879 − 687 =
25. 25.223 − 198 =
26. 26.877 − 197 =
27. 27.579 − 399 =
28. 28.744 − 498 =
29. 29.835 − 468 =
30. 30.265 − 147 =
31. 31.647 − 599 =
32. 32.610 − 498 =
33. 33.871 − 399 =
34. 34.386 − 209 =
35. 35.842 − 669 =
36. 36.965 − 799 =
37. 37.597 − 489 =
38. 38.915 − 398 =
39. 39.571 − 197 =
40. 40.403 − 187 =

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