OK, let's do this. We've got 1309 and 6226 and we're adding them all together.

Step 1: We'll start by adding the digits 9 & 6 in column 1 and get 15.
We'll write down the last digit 5 and carry the 1 to the next column.

Step 2: We'll start by adding the digits 0 & 2 in column 2 and get 3.

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

Step 4: We'll start by adding the digits 1 & 6 in column 4 and get 7.

So, 1309 + 6226 = 7535.

