Okay, we are given 3623 and 2154. 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 & 5 in column 2 and get 7.

Step 3: We'll start by adding the digits 6 & 1 in column 3 and get 7.

Step 4: We'll start by adding the digits 3 & 2 in column 4 and get 5.

So, 3623 + 2154 = 5777.

