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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 850 · 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 22 and take away the sum of its digits. What do you get?
  2. 2.Take 32 and take away the sum of its digits. What do you get?
  3. 3.23? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?604 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.60?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?052 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.8?35 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 18 and take away the sum of its digits. What do you get?
  9. 9.3?32 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 72 and take away the sum of its digits. What do you get?
  11. 11.Take 51 and take away the sum of its digits. What do you get?
  12. 12.?385 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 12 and take away the sum of its digits. What do you get?
  14. 14.293? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 74 and take away the sum of its digits. What do you get?
  16. 16.70?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.20?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 14 and take away the sum of its digits. What do you get?
  19. 19.1?98 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.1?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.508? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?787 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?258 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.38?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?069 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?835 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?363 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.8?07 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 83 and take away the sum of its digits. What do you get?
  30. 30.?055 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.840? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.16?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.73?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 41 and take away the sum of its digits. What do you get?
  35. 35.Take 73 and take away the sum of its digits. What do you get?
  36. 36.?520 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.17?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.2?71 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 76 and take away the sum of its digits. What do you get?
  40. 40.Take 55 and take away the sum of its digits. What do you get?

Answer key

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

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