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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 753 · 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. 1.4?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 55 and take away the sum of its digits. What do you get?
  3. 3.?880 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.1?74 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.2?83 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.733? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?044 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 86 and take away the sum of its digits. What do you get?
  9. 9.?221 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 34 and take away the sum of its digits. What do you get?
  11. 11.?60 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.?785 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 50 and take away the sum of its digits. What do you get?
  14. 14.Take 96 and take away the sum of its digits. What do you get?
  15. 15.2?58 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.5?27 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 70 and take away the sum of its digits. What do you get?
  18. 18.?073 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?276 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 84 and take away the sum of its digits. What do you get?
  21. 21.55? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?796 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 77 and take away the sum of its digits. What do you get?
  24. 24.?500 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 20 and take away the sum of its digits. What do you get?
  26. 26.Take 67 and take away the sum of its digits. What do you get?
  27. 27.Take 30 and take away the sum of its digits. What do you get?
  28. 28.Take 92 and take away the sum of its digits. What do you get?
  29. 29.Take 63 and take away the sum of its digits. What do you get?
  30. 30.1?27 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.71? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.6?22 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.32?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.289? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.68?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 94 and take away the sum of its digits. What do you get?
  37. 37.20?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 93 and take away the sum of its digits. What do you get?
  39. 39.?51 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.7?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. 45
  3. 2
  4. 6
  5. 5
  6. 5
  7. 1
  8. 72
  9. 4
  10. 27
  11. 3
  12. 7
  13. 45
  14. 81
  15. 3
  16. 4
  17. 63
  18. 8
  19. 3
  20. 72
  21. 8
  22. 5
  23. 63
  24. 4
  25. 18
  26. 54
  27. 27
  28. 81
  29. 54
  30. 8
  31. 1
  32. 8
  33. 4
  34. 8
  35. 9
  36. 81
  37. 1
  38. 81
  39. 3
  40. 1

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