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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 73 · 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. 1.7?34 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 45 and take away the sum of its digits. What do you get?
  3. 3.Take 86 and take away the sum of its digits. What do you get?
  4. 4.?292 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 85 and take away the sum of its digits. What do you get?
  6. 6.30? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.6?30 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.4?19 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 74 and take away the sum of its digits. What do you get?
  10. 10.Take 17 and take away the sum of its digits. What do you get?
  11. 11.Take 14 and take away the sum of its digits. What do you get?
  12. 12.?024 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 19 and take away the sum of its digits. What do you get?
  14. 14.7?90 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 16 and take away the sum of its digits. What do you get?
  16. 16.713? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 59 and take away the sum of its digits. What do you get?
  18. 18.Take 63 and take away the sum of its digits. What do you get?
  19. 19.74? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.2?93 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 66 and take away the sum of its digits. What do you get?
  22. 22.62?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.1?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.59?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 97 and take away the sum of its digits. What do you get?
  26. 26.4?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.94? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 20 and take away the sum of its digits. What do you get?
  29. 29.Take 52 and take away the sum of its digits. What do you get?
  30. 30.Take 21 and take away the sum of its digits. What do you get?
  31. 31.Take 54 and take away the sum of its digits. What do you get?
  32. 32.36?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.750? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 81 and take away the sum of its digits. What do you get?
  35. 35.7?10 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.448? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?484 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.223? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?718 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 26 and take away the sum of its digits. What do you get?

Answer key

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

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