OK, let's do this. We've got 1872 and 2935 and we're adding them all 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 7 & 3 in column 2 and get 10.
We'll write down the last digit 0 and carry the 1 to the next column.

Step 3: We'll start by adding the digits 8 & 9 in column 3 and get 18.
We'll write down the last digit 8 and carry the 1 to the next column.

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

So, 1872 + 2935 = 4807.

