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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 737 · 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.?287 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?926 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?600 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 69 and take away the sum of its digits. What do you get?
  5. 5.3?26 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.71?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.2?82 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?78 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 28 and take away the sum of its digits. What do you get?
  10. 10.3?71 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.129? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.269? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 75 and take away the sum of its digits. What do you get?
  14. 14.?256 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?476 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?029 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 57 and take away the sum of its digits. What do you get?
  18. 18.?407 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?67 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.7?55 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 56 and take away the sum of its digits. What do you get?
  22. 22.?046 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?63 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?769 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.34?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.34?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.82?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.181? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.60?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.59? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.13?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.123? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 35 and take away the sum of its digits. What do you get?
  34. 34.Take 71 and take away the sum of its digits. What do you get?
  35. 35.?731 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 31 and take away the sum of its digits. What do you get?
  37. 37.Take 47 and take away the sum of its digits. What do you get?
  38. 38.Take 66 and take away the sum of its digits. What do you get?
  39. 39.6?01 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.230? 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. 1
  3. 3
  4. 54
  5. 7
  6. 7
  7. 6
  8. 3
  9. 18
  10. 7
  11. 6
  12. 1
  13. 63
  14. 5
  15. 1
  16. 7
  17. 45
  18. 7
  19. 5
  20. 1
  21. 45
  22. 8
  23. 9
  24. 5
  25. 6
  26. 2
  27. 1
  28. 8
  29. 5
  30. 4
  31. 3
  32. 3
  33. 27
  34. 63
  35. 7
  36. 27
  37. 36
  38. 54
  39. 2
  40. 4

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