Regarding sqrt, try the Heron-Algorithm to determine sqrt(a):
([] are to be read as indices)

s[0] = a
t[0] = 1

s[n] = (s[n-1]+t[n-1])/2
t[n] = a/s[n]

while n grows s[n] and t[n] approach at each other and sqrt[a].
Imagine a rectangle with side lengths of a and 1. We create iteratively new rectangles with area a but new side lenghts: One is the average of the side lengths of the previous rectangle, the other is clear, when the area remains a.

This rectangle gets closer and closer to be a square and so it's side lenghts to sqrt(a).

The algorithm is quite fast: About six to nine iterations for pocket calculator accuracy - and all you need is basic operations.

Regards,
Werner

Whoops... that one went wrong... sorry about that... can anybody put the previous message in the right thread?

Sorry!

It's better in a new thread.