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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 66 · 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. 1.2?46 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.64?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 43 and take away the sum of its digits. What do you get?
  4. 4.?861 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.647? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?829 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 44 and take away the sum of its digits. What do you get?
  8. 8.Take 23 and take away the sum of its digits. What do you get?
  9. 9.29?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.85? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 36 and take away the sum of its digits. What do you get?
  12. 12.Take 80 and take away the sum of its digits. What do you get?
  13. 13.?839 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?366 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.1?59 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.2?25 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 58 and take away the sum of its digits. What do you get?
  18. 18.Take 72 and take away the sum of its digits. What do you get?
  19. 19.Take 48 and take away the sum of its digits. What do you get?
  20. 20.Take 28 and take away the sum of its digits. What do you get?
  21. 21.Take 69 and take away the sum of its digits. What do you get?
  22. 22.6?23 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.2?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.1?14 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 24 and take away the sum of its digits. What do you get?
  26. 26.?673 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.69?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 33 and take away the sum of its digits. What do you get?
  29. 29.?237 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 46 and take away the sum of its digits. What do you get?
  31. 31.19?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.3?04 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.?417 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.85?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 78 and take away the sum of its digits. What do you get?
  36. 36.?133 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 61 and take away the sum of its digits. What do you get?
  38. 38.?605 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.242? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.41?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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