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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 260 · 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.?203 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.317? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.1?22 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?761 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 15 and take away the sum of its digits. What do you get?
  6. 6.13?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.59?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?354 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.247? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 26 and take away the sum of its digits. What do you get?
  11. 11.62?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.853? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?433 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 36 and take away the sum of its digits. What do you get?
  15. 15.68?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 13 and take away the sum of its digits. What do you get?
  17. 17.87? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?80 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 97 and take away the sum of its digits. What do you get?
  20. 20.Take 77 and take away the sum of its digits. What do you get?
  21. 21.8?44 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.4?62 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.72?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?146 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 61 and take away the sum of its digits. What do you get?
  26. 26.?980 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 41 and take away the sum of its digits. What do you get?
  28. 28.175? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?439 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.281? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 65 and take away the sum of its digits. What do you get?
  32. 32.Take 22 and take away the sum of its digits. What do you get?
  33. 33.Take 17 and take away the sum of its digits. What do you get?
  34. 34.?220 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.10?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.52?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 39 and take away the sum of its digits. What do you get?
  38. 38.Take 54 and take away the sum of its digits. What do you get?
  39. 39.756? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 55 and take away the sum of its digits. What do you get?

Answer key

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

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