Here we go! We're going to add 71 and 8387 together.

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

Step 2: We'll start by adding the digits 7 & 8 in column 2 and get 15.
We'll write down the last digit 5 and carry the 1 to the next column.

Step 3: We'll start by adding the digits 0 & 3 in column 3 and get 4.

Step 4: We'll start by adding the digits 0 & 8 in column 4 and get 8.

So, 71 + 8387 = 8458.

