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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 98 · 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. 1.341? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.88? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.69? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.81?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?183 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.720? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 23 and take away the sum of its digits. What do you get?
  8. 8.2?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 70 and take away the sum of its digits. What do you get?
  10. 10.36?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?193 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.1?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.307? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.8?31 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.69?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?440 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.27?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.1?05 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.490? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.33?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.733? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?393 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?736 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.80? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?178 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.1?28 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.602? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.704? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.72?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.9?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.6?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.697? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.755? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.21?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.808? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.19?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.52?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 55 and take away the sum of its digits. What do you get?
  39. 39.40?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.1?94 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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