We've got two numbers: 6404 and 1124. Let's find their sum.

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

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

Step 3: We'll start by adding the digits 4 & 1 in column 3 and get 5.

Step 4: We'll start by adding the digits 6 & 1 in column 4 and get 7.

So, 6404 + 1124 = 7528.

