We've got two numbers: 1300 and 7591. Let's find their sum.

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

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 3 & 5 in column 3 and get 8.

Step 4: We'll start by adding the digits 1 & 7 in column 4 and get 8.

So, 1300 + 7591 = 8891.

