Let's get this math done. We have 2259 and 6401 and we're going to add them all together.

Step 1: We'll start by adding the digits 9 & 1 in column 1 and get 10.
We'll write down the last digit 0 and carry the 1 to the next column.

Step 2: We'll start by adding the digits 5 & 0 in column 2 and get 6.

Step 3: We'll start by adding the digits 2 & 4 in column 3 and get 6.

Step 4: We'll start by adding the digits 2 & 6 in column 4 and get 8.

So, 2259 + 6401 = 8660.

