We have numbers 700 and 143. Let's start adding them together.

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

Step 2: We'll start by adding the digits 0 & 4 in column 2 and get 4.

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

So, 700 + 143 = 843.

