Let's break this down. We're going to add 5286 and 2900 together.

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

Step 2: We'll start by adding the digits 8 & 0 in column 2 and get 8.

Step 3: We'll start by adding the digits 2 & 9 in column 3 and get 11.
We'll write down the last digit 1 and carry the 1 to the next column.

Step 4: We'll start by adding the digits 5 & 2 in column 4 and get 8.

So, 5286 + 2900 = 8186.

