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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 411 · 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.?998 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.204? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 89 and take away the sum of its digits. What do you get?
  4. 4.Take 15 and take away the sum of its digits. What do you get?
  5. 5.72? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?71 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.271? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?823 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.37?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.142? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 71 and take away the sum of its digits. What do you get?
  12. 12.?476 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 29 and take away the sum of its digits. What do you get?
  14. 14.Take 92 and take away the sum of its digits. What do you get?
  15. 15.Take 52 and take away the sum of its digits. What do you get?
  16. 16.Take 13 and take away the sum of its digits. What do you get?
  17. 17.5?56 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.30?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.74?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.57?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?415 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?250 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.30?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.3?93 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 61 and take away the sum of its digits. What do you get?
  26. 26.?46 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.259? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.6?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?419 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 87 and take away the sum of its digits. What do you get?
  31. 31.Take 67 and take away the sum of its digits. What do you get?
  32. 32.2?05 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.?805 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 94 and take away the sum of its digits. What do you get?
  35. 35.2?63 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.84?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 17 and take away the sum of its digits. What do you get?
  38. 38.?759 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?200 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 68 and take away the sum of its digits. What do you get?

Answer key

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

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