Well -- not being sarcastic -- but the Windows & Mac versions are
*different* in many ways. Just because it's different doesn't make it any
less "easy", but any software has to be learned. Since you don't indicate
anything about what version of Win Excel you're referring to, what method
you're accustomed to, or even what type of "mathematical symbols" you want
to insert it's difficult to give you a comparative answer.
In addition to John's suggestion, though, you might also investigate the use
of the Character Palette provided by OS X. IMO, it is far & away the best
source of anything not directly accessible from the keyboard.
Regards |:>)
Bob Jones
[MVP] Office:Mac