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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 476 · 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.?302 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 51 and take away the sum of its digits. What do you get?
  3. 3.Take 91 and take away the sum of its digits. What do you get?
  4. 4.471? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.8?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.160? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?103 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 31 and take away the sum of its digits. What do you get?
  9. 9.?53 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 50 and take away the sum of its digits. What do you get?
  11. 11.?138 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.?295 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?371 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?14 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 43 and take away the sum of its digits. What do you get?
  16. 16.?296 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 81 and take away the sum of its digits. What do you get?
  18. 18.Take 93 and take away the sum of its digits. What do you get?
  19. 19.Take 84 and take away the sum of its digits. What do you get?
  20. 20.Take 60 and take away the sum of its digits. What do you get?
  21. 21.6?45 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?93 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.310? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 77 and take away the sum of its digits. What do you get?
  25. 25.?239 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.155? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 71 and take away the sum of its digits. What do you get?
  28. 28.89? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.807? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 87 and take away the sum of its digits. What do you get?
  31. 31.4?04 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.46?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.?358 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?577 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.71?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 46 and take away the sum of its digits. What do you get?
  37. 37.826? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?074 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.36?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.8?75 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

  1. 4
  2. 45
  3. 81
  4. 6
  5. 1
  6. 2
  7. 5
  8. 27
  9. 1
  10. 45
  11. 6
  12. 2
  13. 7
  14. 4
  15. 36
  16. 1
  17. 72
  18. 81
  19. 72
  20. 54
  21. 3
  22. 6
  23. 5
  24. 63
  25. 4
  26. 7
  27. 63
  28. 1
  29. 3
  30. 72
  31. 1
  32. 3
  33. 2
  34. 8
  35. 1
  36. 36
  37. 2
  38. 7
  39. 7
  40. 7

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