We have numbers 4305 and 3510. Let's start adding them together.

Step 1: We'll start by adding the digits 5 & 0 in column 1 and get 5.

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

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

Step 4: We'll start by adding the digits 4 & 3 in column 4 and get 7.

So, 4305 + 3510 = 7815.

