Okay, we are tasked with adding 7603 and 64. Let's begin!

Step 1: We'll start by adding the digits 3 & 4 in column 1 and get 7.

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

Step 3: We'll start by adding the digits 6 & 0 in column 3 and get 6.

Step 4: We'll start by adding the digits 7 & 0 in column 4 and get 7.

So, 7603 + 64 = 7667.

