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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 864 · 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.?910 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.4?19 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.77?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 99 and take away the sum of its digits. What do you get?
  5. 5.7?88 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 44 and take away the sum of its digits. What do you get?
  7. 7.16? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?744 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 11 and take away the sum of its digits. What do you get?
  10. 10.Take 18 and take away the sum of its digits. What do you get?
  11. 11.1?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 79 and take away the sum of its digits. What do you get?
  13. 13.7?65 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.67?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.100? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 34 and take away the sum of its digits. What do you get?
  17. 17.?105 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 92 and take away the sum of its digits. What do you get?
  19. 19.Take 93 and take away the sum of its digits. What do you get?
  20. 20.4?68 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?065 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 14 and take away the sum of its digits. What do you get?
  23. 23.Take 59 and take away the sum of its digits. What do you get?
  24. 24.Take 46 and take away the sum of its digits. What do you get?
  25. 25.3?86 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 52 and take away the sum of its digits. What do you get?
  27. 27.54?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.26?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 26 and take away the sum of its digits. What do you get?
  30. 30.?004 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.133? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 51 and take away the sum of its digits. What do you get?
  33. 33.33?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 36 and take away the sum of its digits. What do you get?
  35. 35.242? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 47 and take away the sum of its digits. What do you get?
  37. 37.414? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.206? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.5?30 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 76 and take away the sum of its digits. What do you get?

Answer key

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

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