Let's solve this addition problem. We have 9745 and 394, and we need to add them together.

Step 1: We'll start by adding the digits 5 & 4 in column 1 and get 9.

Step 2: We'll start by adding the digits 4 & 9 in column 2 and get 13.
We'll write down the last digit 3 and carry the 1 to the next column.

Step 3: We'll start by adding the digits 7 & 3 in column 3 and get 11.
We'll write down the last digit 1 and carry the 1 to the next column.

Step 4: We'll start by adding the digits 9 & 0 in column 4 and get 10.
We'll write down the last digit 0 and carry the 1 to the next column.

So, 9745 + 394 = 10139.

