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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 254 · 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. 1.605? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 27 and take away the sum of its digits. What do you get?
  3. 3.332? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 32 and take away the sum of its digits. What do you get?
  5. 5.Take 35 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.Take 14 and take away the sum of its digits. What do you get?
  8. 8.79?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.5?39 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.795? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 38 and take away the sum of its digits. What do you get?
  12. 12.285? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.774? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?374 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?930 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?686 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 91 and take away the sum of its digits. What do you get?
  18. 18.7?84 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?395 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.6?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.101? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 24 and take away the sum of its digits. What do you get?
  23. 23.Take 90 and take away the sum of its digits. What do you get?
  24. 24.13?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.118? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?43 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.791? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.353? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 19 and take away the sum of its digits. What do you get?
  30. 30.26?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?327 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.2?74 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.?836 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 55 and take away the sum of its digits. What do you get?
  35. 35.Take 62 and take away the sum of its digits. What do you get?
  36. 36.18?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 56 and take away the sum of its digits. What do you get?
  38. 38.1?02 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.46?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 66 and take away the sum of its digits. What do you get?

Answer key

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

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