Not to worry, we've got 6546 and 1720. Let's get to adding them!

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

Step 2: We'll start by adding the digits 4 & 2 in column 2 and get 6.

Step 3: We'll start by adding the digits 5 & 7 in column 3 and get 12.
We'll write down the last digit 2 and carry the 1 to the next column.

Step 4: We'll start by adding the digits 6 & 1 in column 4 and get 8.

So, 6546 + 1720 = 8266.

