+297 
+297 this person may be right beyond my knowledge, but actually, it is for the the inputs and outputs for a function. for example, if a table was like this:
| (input) 1 | 2 | 3 | 4 | 5 |
| (output) 7 | 8 | 9 | 10 | 11 |
then the braces for the input would be {1,2,3,4,5}.
also, in a function, for example f(x)=x+1 it would be for {all real numbers}
)
