Let's get this math done. We have 3123 and 5021 and we're going to add them all together.

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

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

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, 3123 + 5021 = 8144.

