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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 438 · 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. 1.2?58 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.22?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?381 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.1?73 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 74 and take away the sum of its digits. What do you get?
  6. 6.64?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 13 and take away the sum of its digits. What do you get?
  8. 8.?814 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 17 and take away the sum of its digits. What do you get?
  10. 10.22?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.16?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.25?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.67?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.8?50 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 95 and take away the sum of its digits. What do you get?
  16. 16.?969 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 72 and take away the sum of its digits. What do you get?
  18. 18.83?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?177 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.7?59 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 42 and take away the sum of its digits. What do you get?
  22. 22.25? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.4?35 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 11 and take away the sum of its digits. What do you get?
  25. 25.500? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.576? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.18?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.16? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 18 and take away the sum of its digits. What do you get?
  30. 30.584? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?880 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?550 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.8?01 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.1?71 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.6?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.57?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 88 and take away the sum of its digits. What do you get?
  38. 38.Take 26 and take away the sum of its digits. What do you get?
  39. 39.130? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 54 and take away the sum of its digits. What do you get?

Answer key

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

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