Let's solve this addition problem. We have 1273 and 2185, and we need to add them together.

Step 1: We'll start by adding the digits 3 & 5 in column 1 and get 8.

Step 2: We'll start by adding the digits 7 & 8 in column 2 and get 15.
We'll write down the last digit 5 and carry the 1 to the next column.

Step 3: We'll start by adding the digits 2 & 1 in column 3 and get 4.

Step 4: We'll start by adding the digits 1 & 2 in column 4 and get 3.

So, 1273 + 2185 = 3458.

