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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 535 · 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.?845 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.4?88 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 72 and take away the sum of its digits. What do you get?
  4. 4.?33 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 67 and take away the sum of its digits. What do you get?
  6. 6.Take 93 and take away the sum of its digits. What do you get?
  7. 7.6?42 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?091 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.7?33 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.1?02 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.239? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.?807 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 83 and take away the sum of its digits. What do you get?
  14. 14.Take 54 and take away the sum of its digits. What do you get?
  15. 15.?34 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?92 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.?344 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?591 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.72?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.82?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 15 and take away the sum of its digits. What do you get?
  22. 22.?420 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 12 and take away the sum of its digits. What do you get?
  24. 24.4?07 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 34 and take away the sum of its digits. What do you get?
  26. 26.70?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.49?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.379? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 94 and take away the sum of its digits. What do you get?
  30. 30.12?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.8?65 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 45 and take away the sum of its digits. What do you get?
  33. 33.47?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.77? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.4?58 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.2?20 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.4?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.75?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 19 and take away the sum of its digits. What do you get?
  40. 40.Take 29 and take away the sum of its digits. What do you get?

Answer key

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

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