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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 813 · 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. 1.206? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?178 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 52 and take away the sum of its digits. What do you get?
  4. 4.74?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 35 and take away the sum of its digits. What do you get?
  6. 6.60?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.5?71 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.234? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 58 and take away the sum of its digits. What do you get?
  10. 10.Take 38 and take away the sum of its digits. What do you get?
  11. 11.275? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.?778 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.139? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.214? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?944 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.3?60 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 14 and take away the sum of its digits. What do you get?
  18. 18.Take 63 and take away the sum of its digits. What do you get?
  19. 19.?025 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.473? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.4?35 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.569? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 66 and take away the sum of its digits. What do you get?
  24. 24.Take 57 and take away the sum of its digits. What do you get?
  25. 25.?443 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.5?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 78 and take away the sum of its digits. What do you get?
  28. 28.221? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.312? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.89?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 68 and take away the sum of its digits. What do you get?
  32. 32.1?90 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.?732 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 77 and take away the sum of its digits. What do you get?
  35. 35.Take 41 and take away the sum of its digits. What do you get?
  36. 36.566? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?21 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 34 and take away the sum of its digits. What do you get?
  39. 39.Take 49 and take away the sum of its digits. What do you get?
  40. 40.84?7 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. 45
  4. 8
  5. 27
  6. 3
  7. 5
  8. 9
  9. 45
  10. 27
  11. 4
  12. 5
  13. 5
  14. 2
  15. 1
  16. 9
  17. 9
  18. 54
  19. 2
  20. 4
  21. 6
  22. 7
  23. 54
  24. 45
  25. 7
  26. 3
  27. 63
  28. 4
  29. 3
  30. 5
  31. 54
  32. 8
  33. 6
  34. 63
  35. 36
  36. 1
  37. 6
  38. 27
  39. 36
  40. 8

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