Let's break this down. We're going to add 4854 and 2688 together.

Step 1: We'll start by adding the digits 4 & 8 in column 1 and get 12.
We'll write down the last digit 2 and carry the 1 to the next column.

Step 2: We'll start by adding the digits 5 & 8 in column 2 and get 14.
We'll write down the last digit 4 and carry the 1 to the next column.

Step 3: We'll start by adding the digits 8 & 6 in column 3 and get 15.
We'll write down the last digit 5 and carry the 1 to the next column.

Step 4: We'll start by adding the digits 4 & 2 in column 4 and get 7.

So, 4854 + 2688 = 7542.

