← Digit-sum magic lesson New set →

Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 185 · 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.?870 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?710 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 59 and take away the sum of its digits. What do you get?
  4. 4.1?35 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 98 and take away the sum of its digits. What do you get?
  6. 6.Take 22 and take away the sum of its digits. What do you get?
  7. 7.Take 60 and take away the sum of its digits. What do you get?
  8. 8.54? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 32 and take away the sum of its digits. What do you get?
  10. 10.Take 70 and take away the sum of its digits. What do you get?
  11. 11.77?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 29 and take away the sum of its digits. What do you get?
  13. 13.?115 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.127? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.34?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?804 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.?61 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.310? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 41 and take away the sum of its digits. What do you get?
  20. 20.Take 79 and take away the sum of its digits. What do you get?
  21. 21.?002 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 75 and take away the sum of its digits. What do you get?
  23. 23.Take 31 and take away the sum of its digits. What do you get?
  24. 24.1?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.318? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?299 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. 28.4?19 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.6?59 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.17?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.53?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 23 and take away the sum of its digits. What do you get?
  33. 33.?580 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 84 and take away the sum of its digits. What do you get?
  35. 35.785? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.41?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?051 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?27 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 57 and take away the sum of its digits. What do you get?
  40. 40.?185 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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