Okay, we are given 1623 and 8244. Let's add them up step by step.

Step 1: We'll start by adding the digits 3 & 4 in column 1 and get 7.

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

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 1 & 8 in column 4 and get 9.

So, 1623 + 8244 = 9867.

