Okay, we are given 1128 and 397. Let's add them up step by step.

Step 1: We'll start by adding the digits 8 & 7 in column 1 and get 15.
We'll write down the last digit 5 and carry the 1 to the next column.

Step 2: We'll start by adding the digits 2 & 9 in column 2 and get 12.
We'll write down the last digit 2 and carry the 1 to the next column.

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

Step 4: We'll start by adding the digits 1 & 0 in column 4 and get 1.

So, 1128 + 397 = 1525.

