Not to worry, we've got 729 and 141. Let's get to adding them!

Step 1: We'll start by adding the digits 9 & 1 in column 1 and get 10.
We'll write down the last digit 0 and carry the 1 to the next column.

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

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

So, 729 + 141 = 870.

