We've got two numbers: 7123 and 2573. Let's find their sum.

Step 1: We'll start by adding the digits 3 & 3 in column 1 and get 6.

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

Step 3: We'll start by adding the digits 1 & 5 in column 3 and get 6.

Step 4: We'll start by adding the digits 7 & 2 in column 4 and get 9.

So, 7123 + 2573 = 9696.

