OK, let's do this. We've got 5392 and 7986 and we're adding them all together.

Step 1: We'll start by adding the digits 2 & 6 in column 1 and get 8.

Step 2: We'll start by adding the digits 9 & 8 in column 2 and get 17.
We'll write down the last digit 7 and carry the 1 to the next column.

Step 3: We'll start by adding the digits 3 & 9 in column 3 and get 13.
We'll write down the last digit 3 and carry the 1 to the next column.

Step 4: We'll start by adding the digits 5 & 7 in column 4 and get 13.
We'll write down the last digit 3 and carry the 1 to the next column.

So, 5392 + 7986 = 13378.

