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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 967 · 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.Take 96 and take away the sum of its digits. What do you get?
  2. 2.?278 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 79 and take away the sum of its digits. What do you get?
  4. 4.5?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?776 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.78?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 29 and take away the sum of its digits. What do you get?
  8. 8.759? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 39 and take away the sum of its digits. What do you get?
  10. 10.38?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 35 and take away the sum of its digits. What do you get?
  12. 12.8?86 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.88?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?36 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.37?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 91 and take away the sum of its digits. What do you get?
  17. 17.1?67 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.5?75 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.3?97 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.84?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 90 and take away the sum of its digits. What do you get?
  22. 22.?392 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 93 and take away the sum of its digits. What do you get?
  24. 24.?080 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.74?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.50?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.472? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.465? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.2?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 13 and take away the sum of its digits. What do you get?
  31. 31.Take 11 and take away the sum of its digits. What do you get?
  32. 32.83?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.108? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 34 and take away the sum of its digits. What do you get?
  35. 35.?313 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 68 and take away the sum of its digits. What do you get?
  37. 37.Take 97 and take away the sum of its digits. What do you get?
  38. 38.Take 59 and take away the sum of its digits. What do you get?
  39. 39.18? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 42 and take away the sum of its digits. What do you get?

Answer key

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

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