Hi Neil,
thanks for your question!
Yes, just as SENO_Media mentioned, formulas work similar to those in Excel. Just add a math expression into a cell, like =D2+D3, which would sum the values from the cells D2 and D3.
You can also use some math functions, which you can find in my first answer in this thread: http://wordpress.org/support/topic/how-to-do-formulas
Regards,
Tobias