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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 242 · 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. 1.2?94 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 15 and take away the sum of its digits. What do you get?
  3. 3.Take 11 and take away the sum of its digits. What do you get?
  4. 4.3?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 13 and take away the sum of its digits. What do you get?
  6. 6.Take 42 and take away the sum of its digits. What do you get?
  7. 7.47?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.29?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.2?04 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.51? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.3?98 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.6?25 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.698? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.147? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.166? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?807 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.4?29 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 61 and take away the sum of its digits. What do you get?
  19. 19.47?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?916 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.7?17 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 73 and take away the sum of its digits. What do you get?
  23. 23.76?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?719 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?825 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?60 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.8?55 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.57?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?485 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 30 and take away the sum of its digits. What do you get?
  31. 31.Take 82 and take away the sum of its digits. What do you get?
  32. 32.Take 80 and take away the sum of its digits. What do you get?
  33. 33.42?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 48 and take away the sum of its digits. What do you get?
  35. 35.?375 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?506 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.81? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?448 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?611 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.1?50 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. 9
  3. 9
  4. 5
  5. 9
  6. 36
  7. 8
  8. 7
  9. 3
  10. 3
  11. 7
  12. 5
  13. 4
  14. 6
  15. 5
  16. 3
  17. 3
  18. 54
  19. 4
  20. 2
  21. 3
  22. 63
  23. 1
  24. 1
  25. 3
  26. 3
  27. 9
  28. 8
  29. 1
  30. 27
  31. 72
  32. 72
  33. 2
  34. 36
  35. 3
  36. 7
  37. 9
  38. 2
  39. 1
  40. 3

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