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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 252 · 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. 1.30?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.797? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.3?74 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 83 and take away the sum of its digits. What do you get?
  5. 5.?174 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.3?45 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 16 and take away the sum of its digits. What do you get?
  8. 8.268? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 30 and take away the sum of its digits. What do you get?
  10. 10.790? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 15 and take away the sum of its digits. What do you get?
  12. 12.839? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 50 and take away the sum of its digits. What do you get?
  14. 14.Take 94 and take away the sum of its digits. What do you get?
  15. 15.627? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?60 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.38?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.390? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.863? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?701 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 55 and take away the sum of its digits. What do you get?
  22. 22.2?58 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?05 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 80 and take away the sum of its digits. What do you get?
  25. 25.?211 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 49 and take away the sum of its digits. What do you get?
  27. 27.Take 41 and take away the sum of its digits. What do you get?
  28. 28.Take 51 and take away the sum of its digits. What do you get?
  29. 29.1?98 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.872? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.562? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?084 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.15?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 71 and take away the sum of its digits. What do you get?
  35. 35.?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?199 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 29 and take away the sum of its digits. What do you get?
  38. 38.Take 12 and take away the sum of its digits. What do you get?
  39. 39.Take 62 and take away the sum of its digits. What do you get?
  40. 40.5?33 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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