We have numbers 142 and 1091. Let's start adding them together.

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

Step 2: We'll start by adding the digits 4 & 9 in column 2 and get 13.
We'll write down the last digit 3 and carry the 1 to the next column.

Step 3: We'll start by adding the digits 1 & 0 in column 3 and get 2.

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

So, 142 + 1091 = 1233.

