Let's solve this addition problem. We have 4542 and 15, and we need to add them 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 & 1 in column 2 and get 5.

Step 3: We'll start by adding the digits 5 & 0 in column 3 and get 5.

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

So, 4542 + 15 = 4557.

