OK, let's do this. We've got 2111 and 6671 and we're adding them all together.

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

Step 2: We'll start by adding the digits 1 & 7 in column 2 and get 8.

Step 3: We'll start by adding the digits 1 & 6 in column 3 and get 7.

Step 4: We'll start by adding the digits 2 & 6 in column 4 and get 8.

So, 2111 + 6671 = 8782.

