Let's break this down. We're going to add 3542 and 7305 together.

Step 1: We'll start by adding the digits 2 & 5 in column 1 and get 7.

Step 2: We'll start by adding the digits 4 & 0 in column 2 and get 4.

Step 3: We'll start by adding the digits 5 & 3 in column 3 and get 8.

Step 4: We'll start by adding the digits 3 & 7 in column 4 and get 10.
We'll write down the last digit 0 and carry the 1 to the next column.

So, 3542 + 7305 = 10847.

