Let's break this down. We're going to add 3307 and 4156 together.

Step 1: We'll start by adding the digits 7 & 6 in column 1 and get 13.
We'll write down the last digit 3 and carry the 1 to the next column.

Step 2: We'll start by adding the digits 0 & 5 in column 2 and get 6.

Step 3: We'll start by adding the digits 3 & 1 in column 3 and get 4.

Step 4: We'll start by adding the digits 3 & 4 in column 4 and get 7.

So, 3307 + 4156 = 7463.

