3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 713 · 40 questions

How to do it in your head (Hundreds first): Keep the first number as it is and split the second into hundreds, tens and ones. Add (or take away) the hundreds first, then the tens. Finish with the ones — bridge through a ten if you need to.

1. 1.720 − 112 =
2. 2.898 − 695 =
3. 3.769 + 326 =
4. 4.592 + 152 =
5. 5.419 − 235 =
6. 6.573 + 551 =
7. 7.773 − 258 =
8. 8.725 + 675 =
9. 9.743 − 196 =
10. 10.199 + 365 =
11. 11.623 − 159 =
12. 12.759 − 478 =
13. 13.789 + 661 =
14. 14.848 − 328 =
15. 15.960 − 241 =
16. 16.595 − 156 =
17. 17.465 + 215 =
18. 18.208 + 186 =
19. 19.564 − 248 =
20. 20.640 − 165 =
21. 21.785 + 647 =
22. 22.752 + 241 =
23. 23.535 + 591 =
24. 24.905 − 483 =
25. 25.503 − 388 =
26. 26.648 + 452 =
27. 27.482 − 301 =
28. 28.751 + 498 =
29. 29.769 − 124 =
30. 30.188 + 301 =
31. 31.897 − 734 =
32. 32.429 − 161 =
33. 33.445 + 509 =
34. 34.931 − 267 =
35. 35.954 − 824 =
36. 36.848 − 584 =
37. 37.257 + 112 =
38. 38.879 − 775 =
39. 39.475 − 149 =
40. 40.613 − 252 =

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