Let's break this down. We're going to add 401 and 1178 together.

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

Step 2: We'll start by adding the digits 0 & 7 in column 2 and get 7.

Step 3: We'll start by adding the digits 4 & 1 in column 3 and get 5.

Step 4: We'll start by adding the digits 0 & 1 in column 4 and get 1.

So, 401 + 1178 = 1579.

