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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 628 · 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. 1.1?71 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 84 and take away the sum of its digits. What do you get?
  3. 3.Take 12 and take away the sum of its digits. What do you get?
  4. 4.2?79 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.418? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 99 and take away the sum of its digits. What do you get?
  7. 7.?010 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?521 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.79? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.1?59 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.77?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.2?98 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.222? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.856? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 95 and take away the sum of its digits. What do you get?
  16. 16.73?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.7?98 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.244? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 26 and take away the sum of its digits. What do you get?
  20. 20.6?16 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 11 and take away the sum of its digits. What do you get?
  22. 22.2?75 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.16?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?770 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.83?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 19 and take away the sum of its digits. What do you get?
  27. 27.3?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?272 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.135? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?545 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.4?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.5?01 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 57 and take away the sum of its digits. What do you get?
  34. 34.?088 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.3?34 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 82 and take away the sum of its digits. What do you get?
  37. 37.2?40 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 24 and take away the sum of its digits. What do you get?
  39. 39.750? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.49?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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