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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 78 · 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. 1.5?56 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.292? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.5?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 82 and take away the sum of its digits. What do you get?
  5. 5.Take 55 and take away the sum of its digits. What do you get?
  6. 6.14? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.27? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?832 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.696? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.10? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 76 and take away the sum of its digits. What do you get?
  12. 12.7?03 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?305 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?841 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.28?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?038 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.59?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 26 and take away the sum of its digits. What do you get?
  19. 19.Take 28 and take away the sum of its digits. What do you get?
  20. 20.?023 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.84?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 30 and take away the sum of its digits. What do you get?
  23. 23.?100 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 18 and take away the sum of its digits. What do you get?
  25. 25.Take 12 and take away the sum of its digits. What do you get?
  26. 26.41?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 53 and take away the sum of its digits. What do you get?
  28. 28.Take 90 and take away the sum of its digits. What do you get?
  29. 29.662? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 86 and take away the sum of its digits. What do you get?
  31. 31.25?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.72?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 34 and take away the sum of its digits. What do you get?
  34. 34.?430 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 95 and take away the sum of its digits. What do you get?
  36. 36.2?66 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?63 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.6?26 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 19 and take away the sum of its digits. What do you get?
  40. 40.89?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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