 Hi and welcome to the session. Let us discuss the following question. Question says, find the values of the letters in the following and give reasons for steps involved. Let us now start with the solution. Now first of all we will rewrite the given puzzle that is a1 plus 1b gives b0. Now we need to find value of two letters that is a and b. Now clearly you can see 1's place of 1 plus b is 0. Now this happens only when value of b is 9. You know that sum of 9 and 1 is 10 and 1's place of 10 is 0. Now when b is equal to 9 then the sum of these two numbers is 90. So we can write when b is equal to 9 then sum of a1 and 1b is 90 as here in the puzzle b0 represents the sum. Now when b is 9 then a1 plus 19 gives 90. Now we need to find the number that must be added to 19 to make the sum equal to 90. Now that number is 71. You know that 71 plus 19 is equal to 90. Other way to find this value is subtract 19 from the sum of the two numbers that is 90. 90 minus 19 is 71. Now we can solve the puzzle as 71 plus 19 gives 90 and we get the value of a as 7. Now we can write for b is equal to 9 and a is equal to 7 a1 plus 1b is equal to b0. Now the puzzle solved is shown below 71 plus 19 gives 90. a is equal to 7 and b is equal to 9 is our required answer. This completes the session. Hope you understood the solution. Take care and bye for now.