OK, let's do this. We've got 5307 and 3373 and we're adding them all together.

Step 1: We'll start by adding the digits 7 & 3 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 0 & 7 in column 2 and get 8.

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

Step 4: We'll start by adding the digits 5 & 3 in column 4 and get 8.

So, 5307 + 3373 = 8680.

