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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 442 · 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. 1.65?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.869? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 65 and take away the sum of its digits. What do you get?
  4. 4.1?40 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.56?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?546 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 99 and take away the sum of its digits. What do you get?
  8. 8.?425 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.7?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.8?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 17 and take away the sum of its digits. What do you get?
  12. 12.?130 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.3?41 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.35?7 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. 16.345? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 97 and take away the sum of its digits. What do you get?
  18. 18.Take 38 and take away the sum of its digits. What do you get?
  19. 19.3?44 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 12 and take away the sum of its digits. What do you get?
  21. 21.291? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 15 and take away the sum of its digits. What do you get?
  23. 23.Take 11 and take away the sum of its digits. What do you get?
  24. 24.Take 93 and take away the sum of its digits. What do you get?
  25. 25.4?20 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.2?70 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.62?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.4?46 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?084 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 95 and take away the sum of its digits. What do you get?
  31. 31.2?27 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.400? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.?042 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.4?82 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 29 and take away the sum of its digits. What do you get?
  36. 36.10?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.57?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?681 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.87?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 20 and take away the sum of its digits. What do you get?

Answer key

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

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