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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 834 · 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.?784 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.7?10 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 50 and take away the sum of its digits. What do you get?
  4. 4.Take 37 and take away the sum of its digits. What do you get?
  5. 5.169? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.691? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.7?61 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.140? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?138 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?971 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 30 and take away the sum of its digits. What do you get?
  12. 12.250? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.238? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 93 and take away the sum of its digits. What do you get?
  15. 15.50?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.25?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 46 and take away the sum of its digits. What do you get?
  18. 18.?759 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.65?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 25 and take away the sum of its digits. What do you get?
  21. 21.Take 55 and take away the sum of its digits. What do you get?
  22. 22.?787 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?602 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.8?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.101? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.22?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?449 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?743 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.473? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?818 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.853? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 13 and take away the sum of its digits. What do you get?
  33. 33.?86 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.170? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 16 and take away the sum of its digits. What do you get?
  36. 36.2?99 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.6?65 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 38 and take away the sum of its digits. What do you get?
  39. 39.?814 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.87?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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