We are presented with 7755 and 8320. Let's work out the sum.

Step 1: We'll start by adding the digits 5 & 0 in column 1 and get 5.

Step 2: We'll start by adding the digits 5 & 2 in column 2 and get 7.

Step 3: We'll start by adding the digits 7 & 3 in column 3 and get 10.
We'll write down the last digit 0 and carry the 1 to the next column.

Step 4: We'll start by adding the digits 7 & 8 in column 4 and get 16.
We'll write down the last digit 6 and carry the 1 to the next column.

So, 7755 + 8320 = 16075.

