Okay, we are tasked with adding 2724 and 6521. Let's begin!

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

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

Step 3: We'll start by adding the digits 7 & 5 in column 3 and get 12.
We'll write down the last digit 2 and carry the 1 to the next column.

Step 4: We'll start by adding the digits 2 & 6 in column 4 and get 9.

So, 2724 + 6521 = 9245.

