What is the answer of binary decimal plus binary?

Answer 1

If you want to add numbers in different bases, in this case decimal and binary, or do any other calculation that involves different bases for that matter, you have to convert all numbers to a single system first - for example, all to decimal. Then you can do the operation. It is really up to you in what base you represent the final answer. In this example, you can convert back to binary, for example.