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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 464 · 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.?458 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.47?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?165 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.169? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 79 and take away the sum of its digits. What do you get?
  6. 6.89?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.278? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 76 and take away the sum of its digits. What do you get?
  9. 9.Take 54 and take away the sum of its digits. What do you get?
  10. 10.Take 42 and take away the sum of its digits. What do you get?
  11. 11.Take 60 and take away the sum of its digits. What do you get?
  12. 12.6?66 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.641? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?105 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.888? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.7?22 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.79?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 41 and take away the sum of its digits. What do you get?
  19. 19.13? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 65 and take away the sum of its digits. What do you get?
  21. 21.Take 75 and take away the sum of its digits. What do you get?
  22. 22.69?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 46 and take away the sum of its digits. What do you get?
  24. 24.58?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 14 and take away the sum of its digits. What do you get?
  26. 26.15?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?11 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 72 and take away the sum of its digits. What do you get?
  29. 29.?367 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?040 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.6?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?776 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.?130 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 90 and take away the sum of its digits. What do you get?
  35. 35.Take 12 and take away the sum of its digits. What do you get?
  36. 36.?206 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 40 and take away the sum of its digits. What do you get?
  38. 38.356? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.243? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.40? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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