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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 240 · 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. 1.71?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 36 and take away the sum of its digits. What do you get?
  3. 3.19? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.1?63 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.61?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.5?10 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?610 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.2?54 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?039 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.251? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 48 and take away the sum of its digits. What do you get?
  12. 12.6?87 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.40? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 11 and take away the sum of its digits. What do you get?
  15. 15.5?01 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.3?61 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 67 and take away the sum of its digits. What do you get?
  18. 18.6?17 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.6?53 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.9?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.570? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?318 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.8?59 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 39 and take away the sum of its digits. What do you get?
  25. 25.29?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 27 and take away the sum of its digits. What do you get?
  27. 27.?777 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.2?07 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?670 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 22 and take away the sum of its digits. What do you get?
  31. 31.?913 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?04 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.3?51 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.1?37 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.85?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 81 and take away the sum of its digits. What do you get?
  37. 37.22?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.44?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 74 and take away the sum of its digits. What do you get?
  40. 40.Take 52 and take away the sum of its digits. What do you get?

Answer key

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

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