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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 349 · 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. 1.11?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?691 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 83 and take away the sum of its digits. What do you get?
  4. 4.Take 72 and take away the sum of its digits. What do you get?
  5. 5.?287 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.4?93 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?95 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 27 and take away the sum of its digits. What do you get?
  9. 9.2?20 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.7?04 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 28 and take away the sum of its digits. What do you get?
  12. 12.?345 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.6?47 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.2?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 82 and take away the sum of its digits. What do you get?
  16. 16.19? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.827? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 25 and take away the sum of its digits. What do you get?
  19. 19.41?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 39 and take away the sum of its digits. What do you get?
  21. 21.?316 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.289? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.53?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.56?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 35 and take away the sum of its digits. What do you get?
  26. 26.48?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 23 and take away the sum of its digits. What do you get?
  28. 28.47?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.737? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.8?49 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.8?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.77?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.32?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 90 and take away the sum of its digits. What do you get?
  35. 35.3?78 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.597? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.55?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 81 and take away the sum of its digits. What do you get?
  39. 39.30? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 74 and take away the sum of its digits. What do you get?

Answer key

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

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