No problem, let's work through this together. We're starting with 1315 and 1557 and adding them all up.

Step 1: We'll start by adding the digits 5 & 7 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 1 & 5 in column 2 and get 7.

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 1 & 1 in column 4 and get 2.

So, 1315 + 1557 = 2872.

