Subtraction by Rounding Worksheet

Mental maths lesson 21: Subtract by rounding up and adding back · Set 969 · 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. 1.566 − 199 =
2. 2.760 − 269 =
3. 3.227 − 198 =
4. 4.970 − 699 =
5. 5.384 − 157 =
6. 6.942 − 799 =
7. 7.882 − 138 =
8. 8.660 − 499 =
9. 9.501 − 128 =
10. 10.693 − 298 =
11. 11.816 − 798 =
12. 12.862 − 799 =
13. 13.959 − 299 =
14. 14.570 − 229 =
15. 15.401 − 119 =
16. 16.397 − 258 =
17. 17.836 − 687 =
18. 18.835 − 267 =
19. 19.849 − 199 =
20. 20.697 − 569 =
21. 21.828 − 447 =
22. 22.790 − 579 =
23. 23.201 − 169 =
24. 24.683 − 599 =
25. 25.788 − 699 =
26. 26.656 − 497 =
27. 27.449 − 397 =
28. 28.486 − 399 =
29. 29.366 − 207 =
30. 30.735 − 589 =
31. 31.446 − 198 =
32. 32.915 − 447 =
33. 33.804 − 617 =
34. 34.720 − 639 =
35. 35.993 − 419 =
36. 36.894 − 799 =
37. 37.686 − 488 =
38. 38.872 − 409 =
39. 39.479 − 299 =
40. 40.430 − 399 =

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