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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 657 · 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.Take 71 and take away the sum of its digits. What do you get?
  2. 2.?09 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 52 and take away the sum of its digits. What do you get?
  4. 4.64?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?515 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 86 and take away the sum of its digits. What do you get?
  7. 7.?332 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.339? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.18?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.5?86 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.68?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.30? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?562 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.1?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 35 and take away the sum of its digits. What do you get?
  16. 16.Take 84 and take away the sum of its digits. What do you get?
  17. 17.5?26 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?195 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 57 and take away the sum of its digits. What do you get?
  20. 20.127? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.58?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.16?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?137 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.2?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.48?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?976 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.42?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?952 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 24 and take away the sum of its digits. What do you get?
  30. 30.Take 32 and take away the sum of its digits. What do you get?
  31. 31.6?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.175? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.?631 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.6?32 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 63 and take away the sum of its digits. What do you get?
  36. 36.5?11 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?064 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?63 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 18 and take away the sum of its digits. What do you get?
  40. 40.?807 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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