Let's get this math done. We have 6635 and 3253 and we're going to add them all together.

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 & 5 in column 2 and get 8.

Step 3: We'll start by adding the digits 6 & 2 in column 3 and get 8.

Step 4: We'll start by adding the digits 6 & 3 in column 4 and get 9.

So, 6635 + 3253 = 9888.

