Let's break this down. We're going to add 2710 and 8400 together.

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

Step 2: We'll start by adding the digits 1 & 0 in column 2 and get 1.

Step 3: We'll start by adding the digits 7 & 4 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 2 & 8 in column 4 and get 11.
We'll write down the last digit 1 and carry the 1 to the next column.

So, 2710 + 8400 = 11110.

