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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 536 · 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.?529 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?402 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.482? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.5?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 54 and take away the sum of its digits. What do you get?
  6. 6.545? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.2?20 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 79 and take away the sum of its digits. What do you get?
  9. 9.?219 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?82 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 19 and take away the sum of its digits. What do you get?
  12. 12.Take 94 and take away the sum of its digits. What do you get?
  13. 13.48?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 62 and take away the sum of its digits. What do you get?
  15. 15.?633 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 66 and take away the sum of its digits. What do you get?
  17. 17.212? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.567? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?080 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.7?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.2?34 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 21 and take away the sum of its digits. What do you get?
  23. 23.37?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.1?76 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.54?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 53 and take away the sum of its digits. What do you get?
  27. 27.684? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?183 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 55 and take away the sum of its digits. What do you get?
  30. 30.?984 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.2?16 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.711? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 50 and take away the sum of its digits. What do you get?
  34. 34.235? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.4?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.69?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.694? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?179 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 99 and take away the sum of its digits. What do you get?
  40. 40.Take 31 and take away the sum of its digits. What do you get?

Answer key

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

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