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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 692 · 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 20 and take away the sum of its digits. What do you get?
  2. 2.Take 99 and take away the sum of its digits. What do you get?
  3. 3.26?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.2?58 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 45 and take away the sum of its digits. What do you get?
  6. 6.?33 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?74 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?406 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?014 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?736 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.2?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.60?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.55?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 77 and take away the sum of its digits. What do you get?
  15. 15.33?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.481? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.7?57 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 32 and take away the sum of its digits. What do you get?
  19. 19.3?08 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 48 and take away the sum of its digits. What do you get?
  21. 21.?677 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.5?17 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.41?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 91 and take away the sum of its digits. What do you get?
  25. 25.2?41 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 14 and take away the sum of its digits. What do you get?
  27. 27.Take 53 and take away the sum of its digits. What do you get?
  28. 28.Take 44 and take away the sum of its digits. What do you get?
  29. 29.Take 96 and take away the sum of its digits. What do you get?
  30. 30.?149 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.53?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.1?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.645? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.596? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 61 and take away the sum of its digits. What do you get?
  36. 36.Take 36 and take away the sum of its digits. What do you get?
  37. 37.?967 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.81?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.57?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.45?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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