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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 615 · 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 14 and take away the sum of its digits. What do you get?
  2. 2.772? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 59 and take away the sum of its digits. What do you get?
  4. 4.Take 61 and take away the sum of its digits. What do you get?
  5. 5.61?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?457 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.194? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.625? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 66 and take away the sum of its digits. What do you get?
  10. 10.Take 12 and take away the sum of its digits. What do you get?
  11. 11.4?35 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 27 and take away the sum of its digits. What do you get?
  13. 13.784? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 15 and take away the sum of its digits. What do you get?
  15. 15.6?86 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 83 and take away the sum of its digits. What do you get?
  17. 17.3?97 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.6?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?03 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.242? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?700 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.3?54 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.14?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.33?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 32 and take away the sum of its digits. What do you get?
  26. 26.71?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 94 and take away the sum of its digits. What do you get?
  28. 28.8?87 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.35?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?093 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.4?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.254? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 81 and take away the sum of its digits. What do you get?
  34. 34.80?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 93 and take away the sum of its digits. What do you get?
  36. 36.Take 80 and take away the sum of its digits. What do you get?
  37. 37.?503 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.360? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 86 and take away the sum of its digits. What do you get?
  40. 40.6?57 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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