OK, let's do this. We've got 131 and 142 and we're adding them all together.

Step 1: We'll start by adding the digits 1 & 2 in column 1 and get 3.

Step 2: We'll start by adding the digits 3 & 4 in column 2 and get 7.

Step 3: We'll start by adding the digits 1 & 1 in column 3 and get 2.

So, 131 + 142 = 273.

