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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 222 · 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.?916 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.65?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.6?60 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.68?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.101? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 26 and take away the sum of its digits. What do you get?
  7. 7.153? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?980 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?220 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.2?88 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.88?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.3?23 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 44 and take away the sum of its digits. What do you get?
  14. 14.36? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.602? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.42?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 89 and take away the sum of its digits. What do you get?
  18. 18.405? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 79 and take away the sum of its digits. What do you get?
  20. 20.Take 42 and take away the sum of its digits. What do you get?
  21. 21.Take 47 and take away the sum of its digits. What do you get?
  22. 22.?804 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 30 and take away the sum of its digits. What do you get?
  24. 24.5?50 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?407 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 13 and take away the sum of its digits. What do you get?
  27. 27.24?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.199? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 25 and take away the sum of its digits. What do you get?
  30. 30.?860 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?790 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?646 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.400? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.2?84 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.4?45 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.367? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 55 and take away the sum of its digits. What do you get?
  38. 38.49?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?856 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.510? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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