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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 21 · 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 54 and take away the sum of its digits. What do you get?
  2. 2.89?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.91? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.653? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 52 and take away the sum of its digits. What do you get?
  6. 6.Take 85 and take away the sum of its digits. What do you get?
  7. 7.?570 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.354? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.780? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?949 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 58 and take away the sum of its digits. What do you get?
  12. 12.898? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.23?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?001 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 18 and take away the sum of its digits. What do you get?
  16. 16.1?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 42 and take away the sum of its digits. What do you get?
  18. 18.Take 12 and take away the sum of its digits. What do you get?
  19. 19.5?46 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?978 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 28 and take away the sum of its digits. What do you get?
  22. 22.7?04 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.52? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.2?83 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.1?37 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 94 and take away the sum of its digits. What do you get?
  27. 27.594? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?420 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 93 and take away the sum of its digits. What do you get?
  30. 30.?289 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.4?73 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.299? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 64 and take away the sum of its digits. What do you get?
  34. 34.78?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 72 and take away the sum of its digits. What do you get?
  36. 36.647? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.57?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.134? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.7?02 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?799 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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