Okay, we are tasked with adding 2120 and 8364. Let's begin!

Step 1: We'll start by adding the digits 0 & 4 in column 1 and get 4.

Step 2: We'll start by adding the digits 2 & 6 in column 2 and get 8.

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

Step 4: We'll start by adding the digits 2 & 8 in column 4 and get 10.
We'll write down the last digit 0 and carry the 1 to the next column.

So, 2120 + 8364 = 10484.

