There are curly brackets and square (or straight) brackets as well as round brackets, which all can be used in different ways, but today we have published two sets of worksheets on round brackets.
The main purpose of round brackets (or parentheses) is to provide further information to a sentence, although it is important to ensure that the sentence would still be complete without the text in brackets. In other words, the information inside the brackets is extra and could be removed. Here is one example:
William I (the first Norman King of England) ordered the compilation of the Domesday Book.
One other point: if the brackets are at the end of the sentence then the full stop, exclamation mark or question mark goes after the final bracket (unless the bracket is a complete sentence).