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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 156 · 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. 1.10?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?275 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.131? 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.?104 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 28 and take away the sum of its digits. What do you get?
  7. 7.Take 93 and take away the sum of its digits. What do you get?
  8. 8.?95 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 57 and take away the sum of its digits. What do you get?
  10. 10.8?13 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 13 and take away the sum of its digits. What do you get?
  12. 12.72?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 48 and take away the sum of its digits. What do you get?
  14. 14.7?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 90 and take away the sum of its digits. What do you get?
  16. 16.183? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.464? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?825 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.8?10 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.41?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 95 and take away the sum of its digits. What do you get?
  22. 22.84? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?60 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 52 and take away the sum of its digits. What do you get?
  25. 25.3?57 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 54 and take away the sum of its digits. What do you get?
  27. 27.344? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.56?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.210? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?300 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.59?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?010 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.23?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.1?33 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.29?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.314? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.343? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.108? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.52?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?314 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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