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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 932 · 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.?183 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 35 and take away the sum of its digits. What do you get?
  3. 3.77?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.2?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?091 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 84 and take away the sum of its digits. What do you get?
  7. 7.Take 29 and take away the sum of its digits. What do you get?
  8. 8.5?33 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.588? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.5?31 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 77 and take away the sum of its digits. What do you get?
  12. 12.5?20 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.87? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 40 and take away the sum of its digits. What do you get?
  15. 15.?652 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.4?27 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 38 and take away the sum of its digits. What do you get?
  18. 18.6?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.62?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.4?57 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 56 and take away the sum of its digits. What do you get?
  22. 22.Take 26 and take away the sum of its digits. What do you get?
  23. 23.1?73 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. 25.82?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?471 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 43 and take away the sum of its digits. What do you get?
  28. 28.40? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.170? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.12?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 93 and take away the sum of its digits. What do you get?
  32. 32.Take 74 and take away the sum of its digits. What do you get?
  33. 33.671? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 79 and take away the sum of its digits. What do you get?
  35. 35.69?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 86 and take away the sum of its digits. What do you get?
  37. 37.1?12 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.4?58 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.104? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?312 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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