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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 824 · 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. 1.89?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?619 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 43 and take away the sum of its digits. What do you get?
  4. 4.201? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 84 and take away the sum of its digits. What do you get?
  6. 6.14? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.206? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 98 and take away the sum of its digits. What do you get?
  9. 9.Take 72 and take away the sum of its digits. What do you get?
  10. 10.Take 36 and take away the sum of its digits. What do you get?
  11. 11.?019 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 14 and take away the sum of its digits. What do you get?
  13. 13.257? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?752 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.546? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.6?28 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 16 and take away the sum of its digits. What do you get?
  18. 18.?890 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.2?18 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?400 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?604 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.20?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.49?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 21 and take away the sum of its digits. What do you get?
  25. 25.Take 95 and take away the sum of its digits. What do you get?
  26. 26.Take 54 and take away the sum of its digits. What do you get?
  27. 27.Take 23 and take away the sum of its digits. What do you get?
  28. 28.Take 89 and take away the sum of its digits. What do you get?
  29. 29.12? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.879? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 85 and take away the sum of its digits. What do you get?
  32. 32.?114 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.675? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?570 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?995 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 32 and take away the sum of its digits. What do you get?
  37. 37.2?97 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 34 and take away the sum of its digits. What do you get?
  39. 39.60?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.5?44 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

  1. 1
  2. 2
  3. 36
  4. 6
  5. 72
  6. 4
  7. 1
  8. 81
  9. 63
  10. 27
  11. 8
  12. 9
  13. 4
  14. 4
  15. 3
  16. 2
  17. 9
  18. 1
  19. 7
  20. 5
  21. 8
  22. 1
  23. 6
  24. 18
  25. 81
  26. 45
  27. 18
  28. 72
  29. 6
  30. 3
  31. 72
  32. 3
  33. 9
  34. 6
  35. 4
  36. 27
  37. 9
  38. 27
  39. 3
  40. 5

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