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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 478 · 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. 1.20?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 95 and take away the sum of its digits. What do you get?
  3. 3.?165 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 19 and take away the sum of its digits. What do you get?
  5. 5.Take 80 and take away the sum of its digits. What do you get?
  6. 6.Take 46 and take away the sum of its digits. What do you get?
  7. 7.Take 60 and take away the sum of its digits. What do you get?
  8. 8.89? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.151? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.14?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 35 and take away the sum of its digits. What do you get?
  12. 12.Take 69 and take away the sum of its digits. What do you get?
  13. 13.Take 83 and take away the sum of its digits. What do you get?
  14. 14.?811 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.684? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.3?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.105? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 26 and take away the sum of its digits. What do you get?
  19. 19.Take 29 and take away the sum of its digits. What do you get?
  20. 20.Take 61 and take away the sum of its digits. What do you get?
  21. 21.4?01 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?256 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 18 and take away the sum of its digits. What do you get?
  24. 24.?245 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.359? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 12 and take away the sum of its digits. What do you get?
  27. 27.287? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?201 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.20?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.87?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 20 and take away the sum of its digits. What do you get?
  32. 32.700? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.8?08 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.57?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.23?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?348 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.40?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?372 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 56 and take away the sum of its digits. What do you get?
  40. 40.Take 32 and take away the sum of its digits. What do you get?

Answer key

  1. 1
  2. 81
  3. 6
  4. 9
  5. 72
  6. 36
  7. 54
  8. 1
  9. 2
  10. 8
  11. 27
  12. 54
  13. 72
  14. 8
  15. 9
  16. 9
  17. 3
  18. 18
  19. 18
  20. 54
  21. 4
  22. 5
  23. 9
  24. 7
  25. 1
  26. 9
  27. 1
  28. 6
  29. 3
  30. 6
  31. 18
  32. 2
  33. 2
  34. 2
  35. 6
  36. 3
  37. 8
  38. 6
  39. 45
  40. 27

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