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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 431 · 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. 1.6?78 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.4?61 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.1?86 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 77 and take away the sum of its digits. What do you get?
  5. 5.?134 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 71 and take away the sum of its digits. What do you get?
  7. 7.627? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.18?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.616? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.8?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.4?53 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.17?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 17 and take away the sum of its digits. What do you get?
  14. 14.59?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.64?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 44 and take away the sum of its digits. What do you get?
  17. 17.157? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 75 and take away the sum of its digits. What do you get?
  19. 19.?730 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?170 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.5?39 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 94 and take away the sum of its digits. What do you get?
  23. 23.112? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 88 and take away the sum of its digits. What do you get?
  25. 25.7?86 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 84 and take away the sum of its digits. What do you get?
  27. 27.Take 68 and take away the sum of its digits. What do you get?
  28. 28.Take 61 and take away the sum of its digits. What do you get?
  29. 29.48?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 15 and take away the sum of its digits. What do you get?
  31. 31.?044 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.464? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 28 and take away the sum of its digits. What do you get?
  34. 34.?696 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?779 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.174? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 57 and take away the sum of its digits. What do you get?
  38. 38.?762 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?278 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 36 and take away the sum of its digits. What do you get?

Answer key

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

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