We've got two numbers: 6544 and 7011. Let's find their sum.

Step 1: We'll start by adding the digits 4 & 1 in column 1 and get 5.

Step 2: We'll start by adding the digits 4 & 1 in column 2 and get 5.

Step 3: We'll start by adding the digits 5 & 0 in column 3 and get 5.

Step 4: We'll start by adding the digits 6 & 7 in column 4 and get 13.
We'll write down the last digit 3 and carry the 1 to the next column.

So, 6544 + 7011 = 13555.

