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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 229 · 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.?169 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 73 and take away the sum of its digits. What do you get?
  3. 3.Take 17 and take away the sum of its digits. What do you get?
  4. 4.86?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 93 and take away the sum of its digits. What do you get?
  6. 6.26? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?62 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. 9.246? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.62?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.16?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.70?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 37 and take away the sum of its digits. What do you get?
  14. 14.Take 86 and take away the sum of its digits. What do you get?
  15. 15.74?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.748? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 30 and take away the sum of its digits. What do you get?
  18. 18.Take 45 and take away the sum of its digits. What do you get?
  19. 19.Take 65 and take away the sum of its digits. What do you get?
  20. 20.Take 50 and take away the sum of its digits. What do you get?
  21. 21.?26 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.1?14 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 62 and take away the sum of its digits. What do you get?
  24. 24.7?63 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.73?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.8?48 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.41?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 69 and take away the sum of its digits. What do you get?
  29. 29.879? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.4?42 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?458 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.602? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.55?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.144? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.52?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.4?84 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.393? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.260? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.524? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.22?6 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. 63
  3. 9
  4. 5
  5. 81
  6. 1
  7. 1
  8. 27
  9. 6
  10. 1
  11. 5
  12. 1
  13. 27
  14. 72
  15. 9
  16. 8
  17. 27
  18. 36
  19. 54
  20. 45
  21. 1
  22. 3
  23. 54
  24. 2
  25. 2
  26. 7
  27. 4
  28. 54
  29. 3
  30. 8
  31. 1
  32. 1
  33. 2
  34. 9
  35. 6
  36. 2
  37. 3
  38. 1
  39. 7
  40. 8

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