We have numbers 5777 and 4122. Let's start adding them together.

Step 1: We'll start by adding the digits 7 & 2 in column 1 and get 9.

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 7 & 1 in column 3 and get 8.

Step 4: We'll start by adding the digits 5 & 4 in column 4 and get 9.

So, 5777 + 4122 = 9899.

