We are presented with 9135 and 6164. Let's work out the sum.

Step 1: We'll start by adding the digits 5 & 4 in column 1 and get 9.

Step 2: We'll start by adding the digits 3 & 6 in column 2 and get 9.

Step 3: We'll start by adding the digits 1 & 1 in column 3 and get 2.

Step 4: We'll start by adding the digits 9 & 6 in column 4 and get 15.
We'll write down the last digit 5 and carry the 1 to the next column.

So, 9135 + 6164 = 15299.

