Okay, we are given 735 and 13. Let's add them up step by step.

Step 1: We'll start by adding the digits 5 & 3 in column 1 and get 8.

Step 2: We'll start by adding the digits 3 & 1 in column 2 and get 4.

Step 3: We'll start by adding the digits 7 & 0 in column 3 and get 7.

So, 735 + 13 = 748.

