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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 69 · 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.?733 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 41 and take away the sum of its digits. What do you get?
  3. 3.?82 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 97 and take away the sum of its digits. What do you get?
  5. 5.?181 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.54?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 31 and take away the sum of its digits. What do you get?
  8. 8.37?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?028 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.4?12 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 64 and take away the sum of its digits. What do you get?
  12. 12.9?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.4?82 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.27? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 74 and take away the sum of its digits. What do you get?
  16. 16.34?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.6?17 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 42 and take away the sum of its digits. What do you get?
  19. 19.?07 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 59 and take away the sum of its digits. What do you get?
  21. 21.Take 71 and take away the sum of its digits. What do you get?
  22. 22.53?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.3?92 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.8?32 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.5?18 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.821? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.83?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.18?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?625 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?346 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.3?10 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?215 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 39 and take away the sum of its digits. What do you get?
  34. 34.5?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.75?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 76 and take away the sum of its digits. What do you get?
  37. 37.?22 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.755? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.11?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 63 and take away the sum of its digits. What do you get?

Answer key

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

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