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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 457 · 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.?805 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?886 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?709 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.4?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.1?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.5?36 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 53 and take away the sum of its digits. What do you get?
  8. 8.?730 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.8?83 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.20?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.2?69 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.481? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.61?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?476 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.23?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 83 and take away the sum of its digits. What do you get?
  17. 17.?624 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.20?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.281? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?606 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?917 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?559 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 95 and take away the sum of its digits. What do you get?
  24. 24.?787 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?05 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 65 and take away the sum of its digits. What do you get?
  27. 27.Take 11 and take away the sum of its digits. What do you get?
  28. 28.Take 22 and take away the sum of its digits. What do you get?
  29. 29.395? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 14 and take away the sum of its digits. What do you get?
  31. 31.Take 80 and take away the sum of its digits. What do you get?
  32. 32.?758 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 21 and take away the sum of its digits. What do you get?
  34. 34.?46 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.351? 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.Take 42 and take away the sum of its digits. What do you get?
  38. 38.Take 72 and take away the sum of its digits. What do you get?
  39. 39.Take 59 and take away the sum of its digits. What do you get?
  40. 40.4?82 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. 5
  3. 2
  4. 5
  5. 2
  6. 4
  7. 45
  8. 8
  9. 8
  10. 6
  11. 1
  12. 5
  13. 2
  14. 1
  15. 8
  16. 72
  17. 6
  18. 8
  19. 7
  20. 6
  21. 1
  22. 8
  23. 81
  24. 5
  25. 4
  26. 54
  27. 9
  28. 18
  29. 1
  30. 9
  31. 72
  32. 7
  33. 18
  34. 8
  35. 9
  36. 81
  37. 36
  38. 63
  39. 45
  40. 4

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