Okay, we are tasked with adding 3390 and 2386. Let's begin!

Step 1: We'll start by adding the digits 0 & 6 in column 1 and get 6.

Step 2: We'll start by adding the digits 9 & 8 in column 2 and get 17.
We'll write down the last digit 7 and carry the 1 to the next column.

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

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

So, 3390 + 2386 = 5776.

