← Add and subtract 3-digit numbers left to right lesson New set →

3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 745 · 40 questions
TalentJR

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.

NameDateTime takenScore ___ / 40
  1. 1.296 + 532 =
  2. 2.309 + 285 =
  3. 3.462 − 207 =
  4. 4.226 + 214 =
  5. 5.539 + 585 =
  6. 6.330 + 291 =
  7. 7.547 − 439 =
  8. 8.640 + 307 =
  9. 9.805 − 561 =
  10. 10.969 − 393 =
  11. 11.522 − 239 =
  12. 12.529 − 144 =
  13. 13.537 + 186 =
  14. 14.162 + 465 =
  15. 15.708 − 299 =
  16. 16.604 − 412 =
  17. 17.602 − 436 =
  18. 18.613 − 477 =
  19. 19.730 − 342 =
  20. 20.730 + 451 =
  21. 21.320 + 427 =
  22. 22.479 − 261 =
  23. 23.694 − 273 =
  24. 24.570 + 257 =
  25. 25.202 + 345 =
  26. 26.454 + 193 =
  27. 27.422 − 292 =
  28. 28.530 − 192 =
  29. 29.647 + 265 =
  30. 30.773 + 553 =
  31. 31.434 − 232 =
  32. 32.662 − 155 =
  33. 33.257 + 248 =
  34. 34.223 + 121 =
  35. 35.423 − 231 =
  36. 36.285 + 293 =
  37. 37.495 − 236 =
  38. 38.464 − 301 =
  39. 39.559 − 152 =
  40. 40.754 + 474 =

Answer key

  1. 828
  2. 594
  3. 255
  4. 440
  5. 1124
  6. 621
  7. 108
  8. 947
  9. 244
  10. 576
  11. 283
  12. 385
  13. 723
  14. 627
  15. 409
  16. 192
  17. 166
  18. 136
  19. 388
  20. 1181
  21. 747
  22. 218
  23. 421
  24. 827
  25. 547
  26. 647
  27. 130
  28. 338
  29. 912
  30. 1326
  31. 202
  32. 507
  33. 505
  34. 344
  35. 192
  36. 578
  37. 259
  38. 163
  39. 407
  40. 1228

Free mental maths lessons, practice and worksheets at talentjr.in/mental-maths