Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 853 · 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. 1.927 − 297 =
2. 2.637 − 597 =
3. 3.619 − 397 =
4. 4.981 − 197 =
5. 5.637 − 499 =
6. 6.292 − 199 =
7. 7.711 − 497 =
8. 8.787 − 597 =
9. 9.608 − 199 =
10. 10.431 − 319 =
11. 11.947 − 578 =
12. 12.757 − 399 =
13. 13.884 − 597 =
14. 14.315 − 199 =
15. 15.735 − 499 =
16. 16.732 − 297 =
17. 17.845 − 798 =
18. 18.436 − 378 =
19. 19.942 − 799 =
20. 20.966 − 698 =
21. 21.393 − 369 =
22. 22.587 − 399 =
23. 23.707 − 477 =
24. 24.865 − 648 =
25. 25.818 − 797 =
26. 26.672 − 608 =
27. 27.835 − 457 =
28. 28.358 − 329 =
29. 29.245 − 199 =
30. 30.840 − 689 =
31. 31.623 − 498 =
32. 32.836 − 597 =
33. 33.877 − 397 =
34. 34.932 − 199 =
35. 35.733 − 698 =
36. 36.574 − 199 =
37. 37.791 − 699 =
38. 38.683 − 459 =
39. 39.723 − 509 =
40. 40.927 − 347 =

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