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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 191 · 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 74 and take away the sum of its digits. What do you get?
  2. 2.?016 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.7?21 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 13 and take away the sum of its digits. What do you get?
  5. 5.Take 39 and take away the sum of its digits. What do you get?
  6. 6.?701 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 36 and take away the sum of its digits. What do you get?
  8. 8.95? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?536 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.6?80 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?673 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.156? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 69 and take away the sum of its digits. What do you get?
  14. 14.3?77 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.80?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 41 and take away the sum of its digits. What do you get?
  17. 17.4?18 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?386 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?160 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 90 and take away the sum of its digits. What do you get?
  21. 21.2?34 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.268? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.2?27 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.6?11 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 89 and take away the sum of its digits. What do you get?
  26. 26.2?80 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 62 and take away the sum of its digits. What do you get?
  28. 28.Take 66 and take away the sum of its digits. What do you get?
  29. 29.48?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.720? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.781? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.504? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.15?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.1?17 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?973 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?527 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 79 and take away the sum of its digits. What do you get?
  38. 38.4?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.44?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.2?15 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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