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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 743 · 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.?42 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 75 and take away the sum of its digits. What do you get?
  3. 3.Take 54 and take away the sum of its digits. What do you get?
  4. 4.794? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 23 and take away the sum of its digits. What do you get?
  6. 6.Take 68 and take away the sum of its digits. What do you get?
  7. 7.Take 20 and take away the sum of its digits. What do you get?
  8. 8.3?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.7?75 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?29 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.8?06 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.5?37 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 35 and take away the sum of its digits. What do you get?
  14. 14.1?60 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?497 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?334 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.70?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?226 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.605? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.314? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.814? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 11 and take away the sum of its digits. What do you get?
  23. 23.?134 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 63 and take away the sum of its digits. What do you get?
  25. 25.5?78 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 21 and take away the sum of its digits. What do you get?
  27. 27.Take 55 and take away the sum of its digits. What do you get?
  28. 28.?268 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 31 and take away the sum of its digits. What do you get?
  30. 30.Take 79 and take away the sum of its digits. What do you get?
  31. 31.?165 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 87 and take away the sum of its digits. What do you get?
  33. 33.7?30 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.560? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.25? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.2?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 14 and take away the sum of its digits. What do you get?
  38. 38.Take 98 and take away the sum of its digits. What do you get?
  39. 39.Take 37 and take away the sum of its digits. What do you get?
  40. 40.?886 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

  1. 3
  2. 63
  3. 45
  4. 7
  5. 18
  6. 54
  7. 18
  8. 7
  9. 8
  10. 7
  11. 4
  12. 3
  13. 27
  14. 2
  15. 7
  16. 8
  17. 2
  18. 8
  19. 7
  20. 1
  21. 5
  22. 9
  23. 1
  24. 54
  25. 7
  26. 18
  27. 45
  28. 2
  29. 27
  30. 63
  31. 6
  32. 72
  33. 8
  34. 7
  35. 2
  36. 2
  37. 9
  38. 81
  39. 27
  40. 5

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