We've got two numbers: 6375 and 8021. Let's find their sum.

Step 1: We'll start by adding the digits 5 & 1 in column 1 and get 6.

Step 2: We'll start by adding the digits 7 & 2 in column 2 and get 9.

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

Step 4: We'll start by adding the digits 6 & 8 in column 4 and get 14.
We'll write down the last digit 4 and carry the 1 to the next column.

So, 6375 + 8021 = 14396.

