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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 531 · 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. 1.35?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.84?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.4?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?01 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 23 and take away the sum of its digits. What do you get?
  6. 6.5?40 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?890 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 67 and take away the sum of its digits. What do you get?
  9. 9.4?34 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 11 and take away the sum of its digits. What do you get?
  11. 11.23?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.1?86 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.103? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?06 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 50 and take away the sum of its digits. What do you get?
  16. 16.Take 48 and take away the sum of its digits. What do you get?
  17. 17.Take 44 and take away the sum of its digits. What do you get?
  18. 18.15?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 26 and take away the sum of its digits. What do you get?
  20. 20.?047 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?074 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.6?15 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.57?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.23?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 92 and take away the sum of its digits. What do you get?
  26. 26.?944 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.4?38 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.3?22 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?839 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?017 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 35 and take away the sum of its digits. What do you get?
  32. 32.Take 15 and take away the sum of its digits. What do you get?
  33. 33.Take 69 and take away the sum of its digits. What do you get?
  34. 34.3?94 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 33 and take away the sum of its digits. What do you get?
  36. 36.Take 53 and take away the sum of its digits. What do you get?
  37. 37.69? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?789 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 93 and take away the sum of its digits. What do you get?
  40. 40.2?89 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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