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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 572 · 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.?031 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 44 and take away the sum of its digits. What do you get?
  3. 3.827? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?419 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?377 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 69 and take away the sum of its digits. What do you get?
  7. 7.?91 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?726 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 45 and take away the sum of its digits. What do you get?
  10. 10.Take 19 and take away the sum of its digits. What do you get?
  11. 11.?269 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 31 and take away the sum of its digits. What do you get?
  13. 13.Take 39 and take away the sum of its digits. What do you get?
  14. 14.?811 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 11 and take away the sum of its digits. What do you get?
  16. 16.Take 67 and take away the sum of its digits. What do you get?
  17. 17.Take 36 and take away the sum of its digits. What do you get?
  18. 18.Take 32 and take away the sum of its digits. What do you get?
  19. 19.15?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.20?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 68 and take away the sum of its digits. What do you get?
  22. 22.Take 66 and take away the sum of its digits. What do you get?
  23. 23.?890 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 25 and take away the sum of its digits. What do you get?
  25. 25.Take 15 and take away the sum of its digits. What do you get?
  26. 26.Take 74 and take away the sum of its digits. What do you get?
  27. 27.894? 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. 29.525? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.82?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?066 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 12 and take away the sum of its digits. What do you get?
  33. 33.?075 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 55 and take away the sum of its digits. What do you get?
  35. 35.?485 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 16 and take away the sum of its digits. What do you get?
  37. 37.1?04 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.848? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.3?95 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.114? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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