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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 493 · 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.Take 33 and take away the sum of its digits. What do you get?
  2. 2.21?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.197? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?830 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 26 and take away the sum of its digits. What do you get?
  6. 6.5?90 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.367? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?548 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.1?73 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 27 and take away the sum of its digits. What do you get?
  11. 11.501? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.525? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 85 and take away the sum of its digits. What do you get?
  14. 14.?836 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 78 and take away the sum of its digits. What do you get?
  16. 16.428? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 91 and take away the sum of its digits. What do you get?
  18. 18.11?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 43 and take away the sum of its digits. What do you get?
  20. 20.?582 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?242 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?949 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.5?37 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.809? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?570 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.82?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 36 and take away the sum of its digits. What do you get?
  28. 28.Take 41 and take away the sum of its digits. What do you get?
  29. 29.Take 20 and take away the sum of its digits. What do you get?
  30. 30.Take 44 and take away the sum of its digits. What do you get?
  31. 31.4?58 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 68 and take away the sum of its digits. What do you get?
  33. 33.640? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 31 and take away the sum of its digits. What do you get?
  35. 35.52?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 29 and take away the sum of its digits. What do you get?
  37. 37.12?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.3?09 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.7?48 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.6?44 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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