Okay, we are given 3120 and 5043. Let's add them up step by step.

Step 1: We'll start by adding the digits 0 & 3 in column 1 and get 3.

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 1 & 0 in column 3 and get 1.

Step 4: We'll start by adding the digits 3 & 5 in column 4 and get 8.

So, 3120 + 5043 = 8163.

