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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 226 · 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. 1.603? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.1?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.5?72 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.57?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.6?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.73?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.4?79 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 82 and take away the sum of its digits. What do you get?
  9. 9.5?27 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?078 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.4?20 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.46?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?682 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.12?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.72?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.42? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.82?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 51 and take away the sum of its digits. What do you get?
  19. 19.Take 45 and take away the sum of its digits. What do you get?
  20. 20.?008 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?876 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 97 and take away the sum of its digits. What do you get?
  23. 23.13?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?64 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 70 and take away the sum of its digits. What do you get?
  26. 26.Take 67 and take away the sum of its digits. What do you get?
  27. 27.760? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 59 and take away the sum of its digits. What do you get?
  29. 29.Take 42 and take away the sum of its digits. What do you get?
  30. 30.?724 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?886 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?082 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.?588 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 85 and take away the sum of its digits. What do you get?
  35. 35.?203 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.21?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.469? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 54 and take away the sum of its digits. What do you get?
  39. 39.Take 58 and take away the sum of its digits. What do you get?
  40. 40.8?31 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. 8
  3. 4
  4. 7
  5. 3
  6. 9
  7. 7
  8. 72
  9. 4
  10. 3
  11. 3
  12. 8
  13. 2
  14. 1
  15. 2
  16. 3
  17. 8
  18. 45
  19. 36
  20. 1
  21. 6
  22. 81
  23. 8
  24. 8
  25. 63
  26. 54
  27. 5
  28. 45
  29. 36
  30. 5
  31. 5
  32. 8
  33. 6
  34. 72
  35. 4
  36. 3
  37. 8
  38. 45
  39. 45
  40. 6

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