We have numbers 6966 and 5721. Let's start adding them together.

Step 1: We'll start by adding the digits 6 & 1 in column 1 and get 7.

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

Step 3: We'll start by adding the digits 9 & 7 in column 3 and get 16.
We'll write down the last digit 6 and carry the 1 to the next column.

Step 4: We'll start by adding the digits 6 & 5 in column 4 and get 12.
We'll write down the last digit 2 and carry the 1 to the next column.

So, 6966 + 5721 = 12687.

