3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 502 · 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. 1.525 − 252 =
2. 2.533 − 365 =
3. 3.648 + 116 =
4. 4.739 − 563 =
5. 5.486 + 639 =
6. 6.898 − 307 =
7. 7.697 + 281 =
8. 8.832 − 303 =
9. 9.780 + 383 =
10. 10.392 + 331 =
11. 11.608 − 184 =
12. 12.849 − 161 =
13. 13.841 − 261 =
14. 14.692 + 173 =
15. 15.565 + 339 =
16. 16.488 − 167 =
17. 17.806 − 434 =
18. 18.706 − 212 =
19. 19.603 + 689 =
20. 20.927 − 581 =
21. 21.883 − 228 =
22. 22.227 + 121 =
23. 23.855 − 627 =
24. 24.509 + 426 =
25. 25.890 − 433 =
26. 26.156 + 144 =
27. 27.930 − 341 =
28. 28.913 − 447 =
29. 29.980 − 271 =
30. 30.160 + 539 =
31. 31.606 − 341 =
32. 32.496 + 536 =
33. 33.457 + 617 =
34. 34.446 + 575 =
35. 35.979 − 792 =
36. 36.379 + 663 =
37. 37.555 − 141 =
38. 38.709 + 279 =
39. 39.195 + 414 =
40. 40.621 − 327 =

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