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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 878 · 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.Take 82 and take away the sum of its digits. What do you get?
  2. 2.?255 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?663 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 50 and take away the sum of its digits. What do you get?
  5. 5.Take 13 and take away the sum of its digits. What do you get?
  6. 6.?886 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.3?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 56 and take away the sum of its digits. What do you get?
  9. 9.3?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.1?51 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.75? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 28 and take away the sum of its digits. What do you get?
  13. 13.82?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?66 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.5?92 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.1?64 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 21 and take away the sum of its digits. What do you get?
  18. 18.41?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 93 and take away the sum of its digits. What do you get?
  20. 20.Take 76 and take away the sum of its digits. What do you get?
  21. 21.Take 54 and take away the sum of its digits. What do you get?
  22. 22.Take 66 and take away the sum of its digits. What do you get?
  23. 23.Take 73 and take away the sum of its digits. What do you get?
  24. 24.3?60 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.156? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.56?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.70?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.30?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.21?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.53?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.490? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?574 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.77?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.82?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.1?92 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 14 and take away the sum of its digits. What do you get?
  37. 37.Take 62 and take away the sum of its digits. What do you get?
  38. 38.Take 25 and take away the sum of its digits. What do you get?
  39. 39.Take 95 and take away the sum of its digits. What do you get?
  40. 40.?023 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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