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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 891 · 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. 1.3?26 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 56 and take away the sum of its digits. What do you get?
  3. 3.8?30 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?102 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 64 and take away the sum of its digits. What do you get?
  6. 6.794? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?797 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.5?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.4?34 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.302? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.114? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.4?46 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 67 and take away the sum of its digits. What do you get?
  14. 14.6?08 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.5?82 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 62 and take away the sum of its digits. What do you get?
  17. 17.Take 77 and take away the sum of its digits. What do you get?
  18. 18.Take 80 and take away the sum of its digits. What do you get?
  19. 19.?30 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?601 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 16 and take away the sum of its digits. What do you get?
  22. 22.4?67 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.25? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 59 and take away the sum of its digits. What do you get?
  25. 25.Take 83 and take away the sum of its digits. What do you get?
  26. 26.74?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 18 and take away the sum of its digits. What do you get?
  28. 28.?266 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 52 and take away the sum of its digits. What do you get?
  30. 30.2?64 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.449? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.8?08 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.175? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.1?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 87 and take away the sum of its digits. What do you get?
  36. 36.?005 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.483? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?644 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.6?32 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.222? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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