← Back to lesson·Advance A · W1 D3 · 2 drill sections · ~4 min

Advance A · Week 1 · Fundamentals

Day 3 Practice Worksheet — Mental Math Shortcuts: ×9, ×11

The lightning-fast logic for specific multipliers.

Name
Date
Score

  1. §1× 11 rule

    ⏱ 2 min · 20 problems

    Timed drill — start a 2-minute timer, then solve in order. Goal: finish under time with full accuracy.

    1. 01.26 × 11=
    2. 02.12 × 11=
    3. 03.71 × 11=
    4. 04.57 × 11=
    5. 05.69 × 11=
    6. 06.58 × 11=
    7. 07.72 × 11=
    8. 08.95 × 11=
    9. 09.12 × 11=
    10. 10.86 × 11=
    11. 11.75 × 11=
    12. 12.73 × 11=
    13. 13.89 × 11=
    14. 14.36 × 11=
    15. 15.24 × 11=
    16. 16.75 × 11=
    17. 17.58 × 11=
    18. 18.37 × 11=
    19. 19.42 × 11=
    20. 20.37 × 11=

  2. §2× 9 rule

    ⏱ 2 min · 20 problems

    Timed drill — start a 2-minute timer, then solve in order. Goal: finish under time with full accuracy.

    1. 01.36 × 9=
    2. 02.94 × 9=
    3. 03.97 × 9=
    4. 04.88 × 9=
    5. 05.33 × 9=
    6. 06.34 × 9=
    7. 07.99 × 9=
    8. 08.13 × 9=
    9. 09.71 × 9=
    10. 10.62 × 9=
    11. 11.21 × 9=
    12. 12.16 × 9=
    13. 13.68 × 9=
    14. 14.96 × 9=
    15. 15.19 × 9=
    16. 16.79 × 9=
    17. 17.43 × 9=
    18. 18.94 × 9=
    19. 19.82 × 9=
    20. 20.57 × 9=

Answer Key

§1 · × 11 rule

  1. 1.286
  2. 2.132
  3. 3.781
  4. 4.627
  5. 5.759
  6. 6.638
  7. 7.792
  8. 8.1045
  9. 9.132
  10. 10.946
  11. 11.825
  12. 12.803
  13. 13.979
  14. 14.396
  15. 15.264
  16. 16.825
  17. 17.638
  18. 18.407
  19. 19.462
  20. 20.407

§2 · × 9 rule

  1. 1.324
  2. 2.846
  3. 3.873
  4. 4.792
  5. 5.297
  6. 6.306
  7. 7.891
  8. 8.117
  9. 9.639
  10. 10.558
  11. 11.189
  12. 12.144
  13. 13.612
  14. 14.864
  15. 15.171
  16. 16.711
  17. 17.387
  18. 18.846
  19. 19.738
  20. 20.513