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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 750 · 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. 1.77?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.686? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.2?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.62?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.778? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 32 and take away the sum of its digits. What do you get?
  7. 7.4?58 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 43 and take away the sum of its digits. What do you get?
  9. 9.63?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 96 and take away the sum of its digits. What do you get?
  11. 11.Take 64 and take away the sum of its digits. What do you get?
  12. 12.Take 94 and take away the sum of its digits. What do you get?
  13. 13.6?97 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?137 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.29?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.6?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 76 and take away the sum of its digits. What do you get?
  18. 18.14? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 71 and take away the sum of its digits. What do you get?
  20. 20.Take 12 and take away the sum of its digits. What do you get?
  21. 21.542? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.179? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?606 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.79? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?237 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 30 and take away the sum of its digits. What do you get?
  27. 27.Take 69 and take away the sum of its digits. What do you get?
  28. 28.Take 47 and take away the sum of its digits. What do you get?
  29. 29.?97 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 88 and take away the sum of its digits. What do you get?
  31. 31.28?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.6?23 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 53 and take away the sum of its digits. What do you get?
  34. 34.?204 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 34 and take away the sum of its digits. What do you get?
  36. 36.Take 51 and take away the sum of its digits. What do you get?
  37. 37.8?16 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?545 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.1?19 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.20?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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