Hi all.

I simply want to know what is the best way to do sums in different bases. Base 10 is easy and we can all do sums with it but what if I had 342 - 173. In base 10 the answer is 169. Fine. But how would I go about solving it in base 9 or 8? What difference, in my mind, do I need to apply to make it easier to do?

I have worked out that 169 in Base 9 is 207 and in Base 8 is 251 but I had to find the answer in Base 10 and then convert it and that just takes ages. There must be a simplier way.

Also, If anyway can find the thread about working out square roots without a calculator I would be grateful.