Let's get this math done. We have 9111 and 3685 and we're going to add them all together.

Step 1: We'll start by adding the digits 1 & 5 in column 1 and get 6.

Step 2: We'll start by adding the digits 1 & 8 in column 2 and get 9.

Step 3: We'll start by adding the digits 1 & 6 in column 3 and get 7.

Step 4: We'll start by adding the digits 9 & 3 in column 4 and get 12.
We'll write down the last digit 2 and carry the 1 to the next column.

So, 9111 + 3685 = 12796.

