We've got two numbers: 705 and 75. Let's find their sum.

Step 1: We'll start by adding the digits 5 & 5 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 0 & 7 in column 2 and get 8.

Step 3: We'll start by adding the digits 7 & 0 in column 3 and get 7.

So, 705 + 75 = 780.

