GMAT Math

Of those topics, you only need to know inequalities, roots and exponents (what you've called 'surds' and 'indices'). You can be asked about maxima and minima, but the question won't require any calculus or any other advanced mathematics (no linear programming, for example). You definitely do not need to know trigonometry, calculus or logarithms, though you do need to know some of the precursors to these subjects- exponent rules, co-ordinate geometry, etc.

I posted a blog here:

www.gmatix.com/blogging/index.php?x=19

which outlines the mathematical topics covered on the GMAT.