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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 109 · 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. 1.6?16 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.5?23 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?389 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.88?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.247? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.534? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?36 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.8?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.184? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?550 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.350? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 77 and take away the sum of its digits. What do you get?
  13. 13.Take 93 and take away the sum of its digits. What do you get?
  14. 14.Take 21 and take away the sum of its digits. What do you get?
  15. 15.792? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.223? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 13 and take away the sum of its digits. What do you get?
  18. 18.200? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 72 and take away the sum of its digits. What do you get?
  20. 20.?940 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?775 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 43 and take away the sum of its digits. What do you get?
  23. 23.60?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.18?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?689 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 36 and take away the sum of its digits. What do you get?
  27. 27.51?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 45 and take away the sum of its digits. What do you get?
  29. 29.Take 41 and take away the sum of its digits. What do you get?
  30. 30.Take 71 and take away the sum of its digits. What do you get?
  31. 31.Take 50 and take away the sum of its digits. What do you get?
  32. 32.?592 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.54?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?02 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.486? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?46 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 23 and take away the sum of its digits. What do you get?
  38. 38.Take 81 and take away the sum of its digits. What do you get?
  39. 39.2?32 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.1?10 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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