3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 520 · 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. 1.883 − 307 =
2. 2.229 + 469 =
3. 3.409 + 275 =
4. 4.594 + 393 =
5. 5.980 − 172 =
6. 6.969 − 533 =
7. 7.607 + 598 =
8. 8.363 + 399 =
9. 9.483 − 347 =
10. 10.456 − 238 =
11. 11.340 + 402 =
12. 12.495 − 287 =
13. 13.571 − 133 =
14. 14.642 + 247 =
15. 15.443 + 122 =
16. 16.868 − 397 =
17. 17.209 + 635 =
18. 18.305 + 573 =
19. 19.589 − 251 =
20. 20.585 + 396 =
21. 21.608 + 293 =
22. 22.563 + 654 =
23. 23.693 + 609 =
24. 24.648 − 157 =
25. 25.578 + 145 =
26. 26.647 + 156 =
27. 27.686 + 408 =
28. 28.173 + 199 =
29. 29.412 − 235 =
30. 30.901 − 709 =
31. 31.664 − 502 =
32. 32.636 + 377 =
33. 33.783 − 619 =
34. 34.370 + 532 =
35. 35.844 − 703 =
36. 36.216 + 651 =
37. 37.711 − 598 =
38. 38.613 − 162 =
39. 39.842 − 621 =
40. 40.871 − 303 =

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