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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 467 · 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. 1.3?94 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 19 and take away the sum of its digits. What do you get?
  3. 3.Take 24 and take away the sum of its digits. What do you get?
  4. 4.?836 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.679? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.2?50 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.92? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 22 and take away the sum of its digits. What do you get?
  9. 9.Take 28 and take away the sum of its digits. What do you get?
  10. 10.?91 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?953 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 59 and take away the sum of its digits. What do you get?
  13. 13.297? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 11 and take away the sum of its digits. What do you get?
  15. 15.?257 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 50 and take away the sum of its digits. What do you get?
  17. 17.Take 98 and take away the sum of its digits. What do you get?
  18. 18.?853 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.59?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 97 and take away the sum of its digits. What do you get?
  21. 21.8?67 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?406 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 70 and take away the sum of its digits. What do you get?
  24. 24.?512 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?71 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.172? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 38 and take away the sum of its digits. What do you get?
  28. 28.?570 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.21?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.5?35 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?622 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?691 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.88?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?005 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.493? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.7?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 91 and take away the sum of its digits. What do you get?
  38. 38.480? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 30 and take away the sum of its digits. What do you get?
  40. 40.Take 23 and take away the sum of its digits. What do you get?

Answer key

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

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