Let's solve this addition problem. We have 6400 and 7776, and we need to add them together.

Step 1: We'll start by adding the digits 0 & 6 in column 1 and get 6.

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

Step 3: We'll start by adding the digits 4 & 7 in column 3 and get 11.
We'll write down the last digit 1 and carry the 1 to the next column.

Step 4: We'll start by adding the digits 6 & 7 in column 4 and get 14.
We'll write down the last digit 4 and carry the 1 to the next column.

So, 6400 + 7776 = 14176.

