Learn how to add the decimals together in simple and easy steps. 1. First practice adding two normal digits using the traditional adding method and get your answer correctly. 2. Now to add the decimals together use the same example by including decimal points to them. 3. The adding will also be the same traditional method except that you have to place a decimal point in the exact location of your answer. 4. Now take another example (E.g.: 3. 33+4. 2) and add it in the same way by placing a zero in the hundredth place.