← Digit-sum magic lesson New set →

Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 64 · 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. 1.385? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 25 and take away the sum of its digits. What do you get?
  3. 3.?686 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 36 and take away the sum of its digits. What do you get?
  5. 5.?49 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 91 and take away the sum of its digits. What do you get?
  7. 7.580? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?627 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?218 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.722? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.1?20 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.?220 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?222 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 64 and take away the sum of its digits. What do you get?
  15. 15.7?03 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.1?55 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.?353 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.8?44 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?12 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.31? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?251 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.298? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 60 and take away the sum of its digits. What do you get?
  24. 24.13?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?103 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?010 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.29?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 71 and take away the sum of its digits. What do you get?
  29. 29.54?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?952 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.78?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 31 and take away the sum of its digits. What do you get?
  33. 33.Take 65 and take away the sum of its digits. What do you get?
  34. 34.2?23 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.46? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 16 and take away the sum of its digits. What do you get?
  37. 37.2?78 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 17 and take away the sum of its digits. What do you get?
  39. 39.6?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.830? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

Free maths tricks lessons, practice and worksheets at talentjr.in/maths-tricks