Let's break this down. We're going to add 1339 and 3748 together.

Step 1: We'll start by adding the digits 9 & 8 in column 1 and get 17.
We'll write down the last digit 7 and carry the 1 to the next column.

Step 2: We'll start by adding the digits 3 & 4 in column 2 and get 8.

Step 3: We'll start by adding the digits 3 & 7 in column 3 and get 10.
We'll write down the last digit 0 and carry the 1 to the next column.

Step 4: We'll start by adding the digits 1 & 3 in column 4 and get 5.

So, 1339 + 3748 = 5087.

