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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 452 · 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. 1.8?77 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 85 and take away the sum of its digits. What do you get?
  3. 3.Take 73 and take away the sum of its digits. What do you get?
  4. 4.4?30 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?046 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 80 and take away the sum of its digits. What do you get?
  7. 7.Take 58 and take away the sum of its digits. What do you get?
  8. 8.43?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?985 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.9?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 83 and take away the sum of its digits. What do you get?
  12. 12.?226 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.452? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.631? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 50 and take away the sum of its digits. What do you get?
  16. 16.6?72 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.3?57 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 44 and take away the sum of its digits. What do you get?
  19. 19.352? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 28 and take away the sum of its digits. What do you get?
  21. 21.Take 34 and take away the sum of its digits. What do you get?
  22. 22.80?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.48?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.1?51 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 17 and take away the sum of its digits. What do you get?
  26. 26.Take 23 and take away the sum of its digits. What do you get?
  27. 27.Take 12 and take away the sum of its digits. What do you get?
  28. 28.114? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?060 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?256 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.620? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?100 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.?609 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.5?54 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?264 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 20 and take away the sum of its digits. What do you get?
  37. 37.2?36 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 61 and take away the sum of its digits. What do you get?
  39. 39.5?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 13 and take away the sum of its digits. What do you get?

Answer key

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

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