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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 614 · 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. 1.443? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?09 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.6?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 36 and take away the sum of its digits. What do you get?
  5. 5.1?38 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.5?97 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 17 and take away the sum of its digits. What do you get?
  8. 8.6?77 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 95 and take away the sum of its digits. What do you get?
  10. 10.30?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?205 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 78 and take away the sum of its digits. What do you get?
  13. 13.78?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 61 and take away the sum of its digits. What do you get?
  15. 15.Take 97 and take away the sum of its digits. What do you get?
  16. 16.?995 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 34 and take away the sum of its digits. What do you get?
  18. 18.7?29 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.25?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 85 and take away the sum of its digits. What do you get?
  21. 21.4?42 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.7?92 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.3?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 13 and take away the sum of its digits. What do you get?
  25. 25.Take 12 and take away the sum of its digits. What do you get?
  26. 26.15?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 64 and take away the sum of its digits. What do you get?
  28. 28.?274 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.31?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?076 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.251? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.26?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 24 and take away the sum of its digits. What do you get?
  34. 34.?042 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.450? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?586 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 53 and take away the sum of its digits. What do you get?
  38. 38.1?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?845 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 38 and take away the sum of its digits. What do you get?

Answer key

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

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