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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 861 · 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 26 and take away the sum of its digits. What do you get?
  2. 2.Take 42 and take away the sum of its digits. What do you get?
  3. 3.Take 33 and take away the sum of its digits. What do you get?
  4. 4.179? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 34 and take away the sum of its digits. What do you get?
  6. 6.60?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.80?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.4?80 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.279? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.89?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 96 and take away the sum of its digits. What do you get?
  12. 12.?917 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?553 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.2?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 68 and take away the sum of its digits. What do you get?
  16. 16.21? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 11 and take away the sum of its digits. What do you get?
  18. 18.1?15 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.7?27 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.433? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 25 and take away the sum of its digits. What do you get?
  22. 22.Take 91 and take away the sum of its digits. What do you get?
  23. 23.Take 90 and take away the sum of its digits. What do you get?
  24. 24.Take 84 and take away the sum of its digits. What do you get?
  25. 25.Take 35 and take away the sum of its digits. What do you get?
  26. 26.753? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 51 and take away the sum of its digits. What do you get?
  28. 28.4?44 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 98 and take away the sum of its digits. What do you get?
  30. 30.Take 27 and take away the sum of its digits. What do you get?
  31. 31.?96 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?229 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.?014 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.13?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?272 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?924 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.2?78 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.4?61 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.3?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.65? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

  1. 18
  2. 36
  3. 27
  4. 1
  5. 27
  6. 4
  7. 3
  8. 6
  9. 9
  10. 4
  11. 81
  12. 1
  13. 5
  14. 6
  15. 54
  16. 6
  17. 9
  18. 2
  19. 2
  20. 8
  21. 18
  22. 81
  23. 81
  24. 72
  25. 27
  26. 3
  27. 45
  28. 6
  29. 81
  30. 18
  31. 3
  32. 5
  33. 4
  34. 9
  35. 7
  36. 3
  37. 1
  38. 7
  39. 6
  40. 7

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