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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 217 · 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 58 and take away the sum of its digits. What do you get?
  2. 2.2?13 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 53 and take away the sum of its digits. What do you get?
  4. 4.Take 83 and take away the sum of its digits. What do you get?
  5. 5.Take 86 and take away the sum of its digits. What do you get?
  6. 6.?592 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 50 and take away the sum of its digits. What do you get?
  8. 8.86?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 30 and take away the sum of its digits. What do you get?
  11. 11.?440 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.4?33 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 18 and take away the sum of its digits. What do you get?
  14. 14.8?21 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?170 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.303? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 81 and take away the sum of its digits. What do you get?
  18. 18.Take 42 and take away the sum of its digits. What do you get?
  19. 19.Take 69 and take away the sum of its digits. What do you get?
  20. 20.4?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.1?35 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 71 and take away the sum of its digits. What do you get?
  23. 23.Take 87 and take away the sum of its digits. What do you get?
  24. 24.7?05 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.20?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 49 and take away the sum of its digits. What do you get?
  27. 27.26?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.779? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?641 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 65 and take away the sum of its digits. What do you get?
  31. 31.15? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?526 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.3?94 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 51 and take away the sum of its digits. What do you get?
  35. 35.?259 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.3?16 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.64?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 17 and take away the sum of its digits. What do you get?
  39. 39.Take 76 and take away the sum of its digits. What do you get?
  40. 40.4?36 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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