Okay, we are tasked with adding 7266 and 5403. Let's begin!

Step 1: We'll start by adding the digits 6 & 3 in column 1 and get 9.

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

Step 3: We'll start by adding the digits 2 & 4 in column 3 and get 6.

Step 4: We'll start by adding the digits 7 & 5 in column 4 and get 12.
We'll write down the last digit 2 and carry the 1 to the next column.

So, 7266 + 5403 = 12669.

