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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 816 · 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.?59 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 83 and take away the sum of its digits. What do you get?
  3. 3.80?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 28 and take away the sum of its digits. What do you get?
  5. 5.34?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.13?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.564? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.4?72 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.6?59 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?570 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?130 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 89 and take away the sum of its digits. What do you get?
  13. 13.24?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?01 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.479? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.300? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.102? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 66 and take away the sum of its digits. What do you get?
  19. 19.?718 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?38 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.7?15 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?619 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.19? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.3?84 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 46 and take away the sum of its digits. What do you get?
  26. 26.1?57 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 50 and take away the sum of its digits. What do you get?
  28. 28.Take 53 and take away the sum of its digits. What do you get?
  29. 29.Take 54 and take away the sum of its digits. What do you get?
  30. 30.73? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 57 and take away the sum of its digits. What do you get?
  32. 32.569? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 22 and take away the sum of its digits. What do you get?
  34. 34.Take 29 and take away the sum of its digits. What do you get?
  35. 35.?276 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?55 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.6?88 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.863? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.28? 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. 4
  2. 72
  3. 1
  4. 18
  5. 4
  6. 5
  7. 3
  8. 5
  9. 7
  10. 6
  11. 5
  12. 72
  13. 6
  14. 8
  15. 7
  16. 6
  17. 6
  18. 54
  19. 2
  20. 7
  21. 5
  22. 2
  23. 8
  24. 3
  25. 36
  26. 5
  27. 45
  28. 45
  29. 45
  30. 8
  31. 45
  32. 7
  33. 18
  34. 18
  35. 3
  36. 8
  37. 5
  38. 1
  39. 8
  40. 54

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