Let's break this down. We're going to add 2071 and 7846 together.

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

Step 2: We'll start by adding the digits 7 & 4 in column 2 and get 11.
We'll write down the last digit 1 and carry the 1 to the next column.

Step 3: We'll start by adding the digits 0 & 8 in column 3 and get 9.

Step 4: We'll start by adding the digits 2 & 7 in column 4 and get 9.

So, 2071 + 7846 = 9917.

