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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 421 · 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. 1.19?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 30 and take away the sum of its digits. What do you get?
  3. 3.?719 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.1?73 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?908 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?752 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.54?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.503? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 39 and take away the sum of its digits. What do you get?
  10. 10.3?92 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.3?02 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 98 and take away the sum of its digits. What do you get?
  13. 13.Take 20 and take away the sum of its digits. What do you get?
  14. 14.896? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.31?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?82 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.2?94 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.796? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 28 and take away the sum of its digits. What do you get?
  20. 20.7?07 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 58 and take away the sum of its digits. What do you get?
  22. 22.Take 45 and take away the sum of its digits. What do you get?
  23. 23.36?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 24 and take away the sum of its digits. What do you get?
  25. 25.?674 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 99 and take away the sum of its digits. What do you get?
  27. 27.Take 23 and take away the sum of its digits. What do you get?
  28. 28.136? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?793 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 50 and take away the sum of its digits. What do you get?
  31. 31.880? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.134? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 91 and take away the sum of its digits. What do you get?
  34. 34.717? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?069 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 69 and take away the sum of its digits. What do you get?
  37. 37.Take 94 and take away the sum of its digits. What do you get?
  38. 38.?827 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 84 and take away the sum of its digits. What do you get?
  40. 40.40?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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