Let's solve this addition problem. We have 1253 and 7413, and we need to add them together.

Step 1: We'll start by adding the digits 3 & 3 in column 1 and get 6.

Step 2: We'll start by adding the digits 5 & 1 in column 2 and get 6.

Step 3: We'll start by adding the digits 2 & 4 in column 3 and get 6.

Step 4: We'll start by adding the digits 1 & 7 in column 4 and get 8.

So, 1253 + 7413 = 8666.

