Alright, let's solve this problem step by step. We have 6213 and 3447 and we're adding them together.

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

Step 2: We'll start by adding the digits 1 & 4 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 6 & 3 in column 4 and get 9.

So, 6213 + 3447 = 9660.

