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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 567 · 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.?501 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 20 and take away the sum of its digits. What do you get?
  3. 3.Take 92 and take away the sum of its digits. What do you get?
  4. 4.?08 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 72 and take away the sum of its digits. What do you get?
  6. 6.?443 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.96? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?476 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?503 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.8?88 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.8?81 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 43 and take away the sum of its digits. What do you get?
  13. 13.Take 75 and take away the sum of its digits. What do you get?
  14. 14.Take 33 and take away the sum of its digits. What do you get?
  15. 15.52?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.651? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 54 and take away the sum of its digits. What do you get?
  18. 18.?318 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.3?42 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?793 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?095 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 52 and take away the sum of its digits. What do you get?
  23. 23.Take 39 and take away the sum of its digits. What do you get?
  24. 24.5?74 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.71?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.231? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.66? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.549? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 13 and take away the sum of its digits. What do you get?
  30. 30.?242 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?608 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.240? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 51 and take away the sum of its digits. What do you get?
  34. 34.537? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.2?09 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?616 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.89?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?911 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 15 and take away the sum of its digits. What do you get?
  40. 40.14?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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