Let's solve this addition problem. We have 4259 and 4127, and we need to add them together.

Step 1: We'll start by adding the digits 9 & 7 in column 1 and get 16.
We'll write down the last digit 6 and carry the 1 to the next column.

Step 2: We'll start by adding the digits 5 & 2 in column 2 and get 8.

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

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

So, 4259 + 4127 = 8386.

