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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 274 · 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. 1.176? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.415? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.2?31 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 79 and take away the sum of its digits. What do you get?
  5. 5.824? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.29?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.15?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 37 and take away the sum of its digits. What do you get?
  9. 9.Take 76 and take away the sum of its digits. What do you get?
  10. 10.Take 80 and take away the sum of its digits. What do you get?
  11. 11.Take 94 and take away the sum of its digits. What do you get?
  12. 12.Take 75 and take away the sum of its digits. What do you get?
  13. 13.75?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?825 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 74 and take away the sum of its digits. What do you get?
  16. 16.748? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 48 and take away the sum of its digits. What do you get?
  18. 18.?139 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 92 and take away the sum of its digits. What do you get?
  20. 20.Take 50 and take away the sum of its digits. What do you get?
  21. 21.?939 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 87 and take away the sum of its digits. What do you get?
  23. 23.36?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.708? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.14? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?123 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.317? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.323? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?001 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?29 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 62 and take away the sum of its digits. What do you get?
  32. 32.490? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.7?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 91 and take away the sum of its digits. What do you get?
  35. 35.447? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?692 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.80?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.2?37 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.10? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?903 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

  1. 4
  2. 8
  3. 3
  4. 63
  5. 4
  6. 8
  7. 7
  8. 27
  9. 63
  10. 72
  11. 81
  12. 63
  13. 3
  14. 3
  15. 63
  16. 8
  17. 36
  18. 5
  19. 81
  20. 45
  21. 6
  22. 72
  23. 5
  24. 3
  25. 4
  26. 3
  27. 7
  28. 1
  29. 8
  30. 7
  31. 54
  32. 5
  33. 6
  34. 81
  35. 3
  36. 1
  37. 1
  38. 6
  39. 8
  40. 6

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