We have numbers 4212 and 2181. Let's start adding them together.

Step 1: We'll start by adding the digits 2 & 1 in column 1 and get 3.

Step 2: We'll start by adding the digits 1 & 8 in column 2 and get 9.

Step 3: We'll start by adding the digits 2 & 1 in column 3 and get 3.

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

So, 4212 + 2181 = 6393.

