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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 127 · 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. 1.609? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.4?18 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?894 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 45 and take away the sum of its digits. What do you get?
  5. 5.Take 20 and take away the sum of its digits. What do you get?
  6. 6.?807 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.34?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.416? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.1?78 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?103 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.63?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.5?19 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 34 and take away the sum of its digits. What do you get?
  14. 14.?011 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.246? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 91 and take away the sum of its digits. What do you get?
  17. 17.?607 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.20? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.221? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.628? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 28 and take away the sum of its digits. What do you get?
  22. 22.Take 75 and take away the sum of its digits. What do you get?
  23. 23.Take 66 and take away the sum of its digits. What do you get?
  24. 24.61?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?515 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.13?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.70?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 13 and take away the sum of its digits. What do you get?
  29. 29.Take 15 and take away the sum of its digits. What do you get?
  30. 30.265? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 71 and take away the sum of its digits. What do you get?
  32. 32.Take 26 and take away the sum of its digits. What do you get?
  33. 33.?443 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?471 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?098 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 87 and take away the sum of its digits. What do you get?
  37. 37.27?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 37 and take away the sum of its digits. What do you get?
  39. 39.?076 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 79 and take away the sum of its digits. What do you get?

Answer key

  1. 3
  2. 5
  3. 6
  4. 36
  5. 18
  6. 3
  7. 7
  8. 7
  9. 2
  10. 5
  11. 9
  12. 3
  13. 27
  14. 7
  15. 6
  16. 81
  17. 5
  18. 7
  19. 4
  20. 2
  21. 18
  22. 63
  23. 54
  24. 2
  25. 7
  26. 6
  27. 6
  28. 9
  29. 9
  30. 5
  31. 63
  32. 18
  33. 7
  34. 6
  35. 1
  36. 72
  37. 2
  38. 27
  39. 5
  40. 63

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