Let's solve this addition problem. We have 8703 and 1242, and we need to add them together.

Step 1: We'll start by adding the digits 3 & 2 in column 1 and get 5.

Step 2: We'll start by adding the digits 0 & 4 in column 2 and get 4.

Step 3: We'll start by adding the digits 7 & 2 in column 3 and get 9.

Step 4: We'll start by adding the digits 8 & 1 in column 4 and get 9.

So, 8703 + 1242 = 9945.

