>>715351754It doesn't mean anything in that context because it encloses a single number.
Also this guy is retarded
>>715351853. The various differen parens are just deeper levels of grouping so you don't get confused. So (((3+2) * 5) + 6) * 7 gets written as {[(3+2) * 5] + 6} * 7. For this short example it's pointless but for longer ones it helps in understanding which group ends where.
Also the names are parentheses(), square brackets[], curly braces{}. Though some people call them all brackets to confuse you.