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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 719 · 40 questions
TalentJR

The trick (Digits add to the 9 table): Add the digits you can see. Find the next number in the 9 table (9, 18, 27 …) above that total. The hidden digit is the difference. (Any number minus its digit sum is in the 9 table too.)

NameDateTime takenScore ___ / 40
  1. 1.24?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.86?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.792? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 52 and take away the sum of its digits. What do you get?
  5. 5.672? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 19 and take away the sum of its digits. What do you get?
  7. 7.?086 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?197 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.5?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.114? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 11 and take away the sum of its digits. What do you get?
  12. 12.Take 81 and take away the sum of its digits. What do you get?
  13. 13.Take 31 and take away the sum of its digits. What do you get?
  14. 14.Take 43 and take away the sum of its digits. What do you get?
  15. 15.Take 95 and take away the sum of its digits. What do you get?
  16. 16.?332 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 62 and take away the sum of its digits. What do you get?
  18. 18.Take 85 and take away the sum of its digits. What do you get?
  19. 19.40?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 44 and take away the sum of its digits. What do you get?
  21. 21.Take 40 and take away the sum of its digits. What do you get?
  22. 22.2?86 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 14 and take away the sum of its digits. What do you get?
  24. 24.3?58 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?42 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 96 and take away the sum of its digits. What do you get?
  27. 27.?660 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.5?86 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 17 and take away the sum of its digits. What do you get?
  30. 30.Take 70 and take away the sum of its digits. What do you get?
  31. 31.Take 35 and take away the sum of its digits. What do you get?
  32. 32.?201 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.4?04 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.4?62 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?728 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?14 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 63 and take away the sum of its digits. What do you get?
  38. 38.Take 61 and take away the sum of its digits. What do you get?
  39. 39.Take 56 and take away the sum of its digits. What do you get?
  40. 40.Take 12 and take away the sum of its digits. What do you get?

Answer key

  1. 9
  2. 5
  3. 9
  4. 45
  5. 3
  6. 9
  7. 4
  8. 1
  9. 6
  10. 3
  11. 9
  12. 72
  13. 27
  14. 36
  15. 81
  16. 1
  17. 54
  18. 72
  19. 3
  20. 36
  21. 36
  22. 2
  23. 9
  24. 2
  25. 3
  26. 81
  27. 6
  28. 8
  29. 9
  30. 63
  31. 27
  32. 6
  33. 1
  34. 6
  35. 1
  36. 4
  37. 54
  38. 54
  39. 45
  40. 9

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