3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 580 · 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. 1.857 − 622 =
2. 2.781 − 389 =
3. 3.872 − 406 =
4. 4.948 − 689 =
5. 5.429 + 219 =
6. 6.624 − 215 =
7. 7.389 + 151 =
8. 8.482 + 675 =
9. 9.604 + 453 =
10. 10.634 − 252 =
11. 11.545 − 392 =
12. 12.523 − 165 =
13. 13.794 − 263 =
14. 14.974 − 696 =
15. 15.430 + 246 =
16. 16.526 + 234 =
17. 17.554 − 365 =
18. 18.600 − 142 =
19. 19.242 + 307 =
20. 20.244 + 441 =
21. 21.489 − 262 =
22. 22.846 − 129 =
23. 23.785 + 611 =
24. 24.928 − 821 =
25. 25.754 − 231 =
26. 26.534 + 121 =
27. 27.457 + 552 =
28. 28.629 + 498 =
29. 29.764 − 373 =
30. 30.515 + 112 =
31. 31.236 + 371 =
32. 32.651 − 522 =
33. 33.495 − 236 =
34. 34.756 + 687 =
35. 35.421 + 488 =
36. 36.544 + 592 =
37. 37.277 + 139 =
38. 38.219 + 465 =
39. 39.481 − 308 =
40. 40.338 + 448 =

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