3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 421 · 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. 1.616 − 229 =
2. 2.764 − 426 =
3. 3.167 + 311 =
4. 4.711 + 253 =
5. 5.795 − 209 =
6. 6.755 − 611 =
7. 7.780 + 279 =
8. 8.274 + 422 =
9. 9.173 + 467 =
10. 10.654 − 385 =
11. 11.407 + 364 =
12. 12.443 − 265 =
13. 13.647 − 321 =
14. 14.544 + 304 =
15. 15.632 − 135 =
16. 16.615 − 296 =
17. 17.966 − 652 =
18. 18.505 − 253 =
19. 19.521 + 538 =
20. 20.720 − 192 =
21. 21.732 − 443 =
22. 22.146 + 507 =
23. 23.488 − 335 =
24. 24.952 − 751 =
25. 25.606 + 472 =
26. 26.261 + 122 =
27. 27.135 + 271 =
28. 28.957 − 772 =
29. 29.719 + 267 =
30. 30.792 − 138 =
31. 31.704 − 152 =
32. 32.444 + 346 =
33. 33.541 − 184 =
34. 34.365 + 568 =
35. 35.646 + 192 =
36. 36.547 − 441 =
37. 37.621 − 211 =
38. 38.393 + 603 =
39. 39.797 − 273 =
40. 40.680 − 112 =

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