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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 315 · 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. 1.28?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 61 and take away the sum of its digits. What do you get?
  3. 3.Take 16 and take away the sum of its digits. What do you get?
  4. 4.471? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.45?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 99 and take away the sum of its digits. What do you get?
  7. 7.?14 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.60?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.5?43 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 56 and take away the sum of its digits. What do you get?
  11. 11.3?56 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.779? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.11?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 97 and take away the sum of its digits. What do you get?
  15. 15.Take 50 and take away the sum of its digits. What do you get?
  16. 16.72?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.5?44 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 34 and take away the sum of its digits. What do you get?
  19. 19.Take 33 and take away the sum of its digits. What do you get?
  20. 20.102? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?481 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.14?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 57 and take away the sum of its digits. What do you get?
  24. 24.3?89 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.54?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 47 and take away the sum of its digits. What do you get?
  27. 27.8?58 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?676 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 66 and take away the sum of its digits. What do you get?
  30. 30.87?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 80 and take away the sum of its digits. What do you get?
  32. 32.Take 38 and take away the sum of its digits. What do you get?
  33. 33.744? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?424 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.49?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 73 and take away the sum of its digits. What do you get?
  37. 37.694? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.2?47 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.Take 62 and take away the sum of its digits. What do you get?

Answer key

  1. 5
  2. 54
  3. 9
  4. 6
  5. 5
  6. 81
  7. 4
  8. 8
  9. 6
  10. 45
  11. 4
  12. 4
  13. 7
  14. 81
  15. 45
  16. 4
  17. 5
  18. 27
  19. 27
  20. 6
  21. 5
  22. 8
  23. 45
  24. 7
  25. 9
  26. 36
  27. 6
  28. 8
  29. 54
  30. 3
  31. 72
  32. 27
  33. 3
  34. 8
  35. 5
  36. 63
  37. 8
  38. 5
  39. 72
  40. 54

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