OK, let's do this. We've got 771 and 117 and we're adding them all 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 & 1 in column 2 and get 8.

Step 3: We'll start by adding the digits 7 & 1 in column 3 and get 8.

So, 771 + 117 = 888.

