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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 993 · 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. 1.215? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?769 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?106 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 74 and take away the sum of its digits. What do you get?
  5. 5.?18 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 83 and take away the sum of its digits. What do you get?
  7. 7.Take 23 and take away the sum of its digits. What do you get?
  8. 8.Take 71 and take away the sum of its digits. What do you get?
  9. 9.Take 53 and take away the sum of its digits. What do you get?
  10. 10.4?92 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 25 and take away the sum of its digits. What do you get?
  12. 12.50?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.69?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 75 and take away the sum of its digits. What do you get?
  15. 15.Take 49 and take away the sum of its digits. What do you get?
  16. 16.Take 85 and take away the sum of its digits. What do you get?
  17. 17.6?48 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?222 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 33 and take away the sum of its digits. What do you get?
  20. 20.?629 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 44 and take away the sum of its digits. What do you get?
  22. 22.7?37 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?230 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.2?36 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.20?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?17 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.6?65 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.296? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.9?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.3?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.16?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?069 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.776? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.842? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.4?52 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?822 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?33 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 65 and take away the sum of its digits. What do you get?
  39. 39.Take 41 and take away the sum of its digits. What do you get?
  40. 40.Take 21 and take away the sum of its digits. What do you get?

Answer key

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

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