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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 367 · 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 61 and take away the sum of its digits. What do you get?
  2. 2.Take 27 and take away the sum of its digits. What do you get?
  3. 3.Take 83 and take away the sum of its digits. What do you get?
  4. 4.Take 19 and take away the sum of its digits. What do you get?
  5. 5.9?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?25 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 12 and take away the sum of its digits. What do you get?
  8. 8.?793 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 54 and take away the sum of its digits. What do you get?
  10. 10.Take 63 and take away the sum of its digits. What do you get?
  11. 11.44?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 28 and take away the sum of its digits. What do you get?
  13. 13.7?60 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 77 and take away the sum of its digits. What do you get?
  15. 15.?647 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 55 and take away the sum of its digits. What do you get?
  17. 17.Take 18 and take away the sum of its digits. What do you get?
  18. 18.84?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 34 and take away the sum of its digits. What do you get?
  20. 20.1?90 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.442? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.11?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?31 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?458 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.80? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 87 and take away the sum of its digits. What do you get?
  27. 27.Take 92 and take away the sum of its digits. What do you get?
  28. 28.422? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 39 and take away the sum of its digits. What do you get?
  30. 30.53?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.89? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 73 and take away the sum of its digits. What do you get?
  33. 33.Take 95 and take away the sum of its digits. What do you get?
  34. 34.Take 11 and take away the sum of its digits. What do you get?
  35. 35.Take 65 and take away the sum of its digits. What do you get?
  36. 36.71?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?968 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 97 and take away the sum of its digits. What do you get?
  39. 39.2?31 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.12?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

  1. 54
  2. 18
  3. 72
  4. 9
  5. 9
  6. 2
  7. 9
  8. 8
  9. 45
  10. 54
  11. 3
  12. 18
  13. 5
  14. 63
  15. 1
  16. 45
  17. 9
  18. 6
  19. 27
  20. 8
  21. 8
  22. 8
  23. 5
  24. 1
  25. 1
  26. 72
  27. 81
  28. 1
  29. 27
  30. 8
  31. 1
  32. 63
  33. 81
  34. 9
  35. 54
  36. 9
  37. 4
  38. 81
  39. 3
  40. 6

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