We have numbers 2100 and 5090. Let's start adding them together.

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

Step 2: We'll start by adding the digits 0 & 9 in column 2 and get 9.

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

Step 4: We'll start by adding the digits 2 & 5 in column 4 and get 7.

So, 2100 + 5090 = 7190.

