No problem, let's work through this together. We're starting with 5113 and 1820 and adding them all up.

Step 1: We'll start by adding the digits 3 & 0 in column 1 and get 3.

Step 2: We'll start by adding the digits 1 & 2 in column 2 and get 3.

Step 3: We'll start by adding the digits 1 & 8 in column 3 and get 9.

Step 4: We'll start by adding the digits 5 & 1 in column 4 and get 6.

So, 5113 + 1820 = 6933.

