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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 175 · 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?94 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 19 and take away the sum of its digits. What do you get?
  3. 3.?37 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.585? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 38 and take away the sum of its digits. What do you get?
  6. 6.Take 36 and take away the sum of its digits. What do you get?
  7. 7.?497 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.5?28 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?388 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.822? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?833 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 31 and take away the sum of its digits. What do you get?
  13. 13.5?06 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.3?13 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.502? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.200? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 77 and take away the sum of its digits. What do you get?
  18. 18.3?10 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.456? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.120? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.2?43 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.3?72 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 48 and take away the sum of its digits. What do you get?
  24. 24.2?18 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 86 and take away the sum of its digits. What do you get?
  26. 26.2?54 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 22 and take away the sum of its digits. What do you get?
  28. 28.64?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 11 and take away the sum of its digits. What do you get?
  30. 30.Take 72 and take away the sum of its digits. What do you get?
  31. 31.2?55 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 59 and take away the sum of its digits. What do you get?
  33. 33.Take 54 and take away the sum of its digits. What do you get?
  34. 34.97? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.13?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 88 and take away the sum of its digits. What do you get?
  37. 37.84? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.25?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?412 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 87 and take away the sum of its digits. What do you get?

Answer key

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

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