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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 111 · 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. 1.496? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 21 and take away the sum of its digits. What do you get?
  3. 3.?01 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 59 and take away the sum of its digits. What do you get?
  5. 5.3?16 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.364? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?32 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 98 and take away the sum of its digits. What do you get?
  9. 9.?319 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.48?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 32 and take away the sum of its digits. What do you get?
  12. 12.97? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?664 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.42?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?443 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?401 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 90 and take away the sum of its digits. What do you get?
  18. 18.?106 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.85?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?047 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 26 and take away the sum of its digits. What do you get?
  22. 22.816? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.2?89 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 43 and take away the sum of its digits. What do you get?
  25. 25.71?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.45? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.27?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.2?17 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.68?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?840 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.1?84 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 12 and take away the sum of its digits. What do you get?
  33. 33.?280 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.730? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.7?16 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?957 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.8?10 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 34 and take away the sum of its digits. What do you get?
  39. 39.?800 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.59?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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