← Digit-sum magic lesson New set →

Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 192 · 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 23 and take away the sum of its digits. What do you get?
  2. 2.80?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 17 and take away the sum of its digits. What do you get?
  4. 4.Take 87 and take away the sum of its digits. What do you get?
  5. 5.?777 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 97 and take away the sum of its digits. What do you get?
  7. 7.20?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 46 and take away the sum of its digits. What do you get?
  9. 9.760? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?147 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 40 and take away the sum of its digits. What do you get?
  12. 12.32?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?015 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.101? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.5?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?559 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.1?88 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.4?49 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 78 and take away the sum of its digits. What do you get?
  20. 20.Take 27 and take away the sum of its digits. What do you get?
  21. 21.Take 22 and take away the sum of its digits. What do you get?
  22. 22.6?76 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.170? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.61?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 90 and take away the sum of its digits. What do you get?
  26. 26.262? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?05 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 42 and take away the sum of its digits. What do you get?
  29. 29.79?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.5?16 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.5?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 73 and take away the sum of its digits. What do you get?
  33. 33.?741 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.470? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 45 and take away the sum of its digits. What do you get?
  36. 36.?791 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.2?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 70 and take away the sum of its digits. What do you get?
  39. 39.73?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.275? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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