Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 748 · 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. 1.967 − 598 =
2. 2.965 − 399 =
3. 3.944 − 299 =
4. 4.405 − 297 =
5. 5.679 − 508 =
6. 6.819 − 798 =
7. 7.628 − 418 =
8. 8.393 − 219 =
9. 9.832 − 358 =
10. 10.193 − 168 =
11. 11.462 − 299 =
12. 12.998 − 677 =
13. 13.343 − 138 =
14. 14.855 − 399 =
15. 15.844 − 298 =
16. 16.758 − 398 =
17. 17.664 − 398 =
18. 18.553 − 299 =
19. 19.624 − 298 =
20. 20.664 − 298 =
21. 21.369 − 197 =
22. 22.839 − 509 =
23. 23.833 − 598 =
24. 24.593 − 439 =
25. 25.777 − 368 =
26. 26.615 − 197 =
27. 27.780 − 498 =
28. 28.834 − 678 =
29. 29.691 − 297 =
30. 30.844 − 119 =
31. 31.821 − 799 =
32. 32.386 − 159 =
33. 33.761 − 697 =
34. 34.472 − 299 =
35. 35.505 − 378 =
36. 36.782 − 658 =
37. 37.946 − 399 =
38. 38.834 − 798 =
39. 39.560 − 399 =
40. 40.888 − 458 =

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