Okay, we are given 3231 and 7521. Let's add them up step by step.

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

Step 2: We'll start by adding the digits 3 & 2 in column 2 and get 5.

Step 3: We'll start by adding the digits 2 & 5 in column 3 and get 7.

Step 4: We'll start by adding the digits 3 & 7 in column 4 and get 10.
We'll write down the last digit 0 and carry the 1 to the next column.

So, 3231 + 7521 = 10752.

