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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 612 · 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.?026 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 83 and take away the sum of its digits. What do you get?
  3. 3.77?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 70 and take away the sum of its digits. What do you get?
  5. 5.?096 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?09 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 98 and take away the sum of its digits. What do you get?
  8. 8.?01 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 81 and take away the sum of its digits. What do you get?
  10. 10.2?54 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 58 and take away the sum of its digits. What do you get?
  12. 12.6?17 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 30 and take away the sum of its digits. What do you get?
  14. 14.Take 71 and take away the sum of its digits. What do you get?
  15. 15.Take 51 and take away the sum of its digits. What do you get?
  16. 16.2?21 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.2?28 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?020 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 75 and take away the sum of its digits. What do you get?
  20. 20.Take 89 and take away the sum of its digits. What do you get?
  21. 21.?249 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.573? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?425 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.2?69 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.698? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.2?06 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.7?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.370? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.89?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 92 and take away the sum of its digits. What do you get?
  31. 31.?794 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.2?96 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.?253 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 69 and take away the sum of its digits. What do you get?
  35. 35.Take 29 and take away the sum of its digits. What do you get?
  36. 36.?339 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?500 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 48 and take away the sum of its digits. What do you get?
  39. 39.59?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 86 and take away the sum of its digits. What do you get?

Answer key

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

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