Okay, we are tasked with adding 2374 and 2578. Let's begin!

Step 1: We'll start by adding the digits 4 & 8 in column 1 and get 12.
We'll write down the last digit 2 and carry the 1 to the next column.

Step 2: We'll start by adding the digits 7 & 7 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 3 & 5 in column 3 and get 9.

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

So, 2374 + 2578 = 4952.

