I'm new to the forum so hello!

Apologies if this question is too simple, if it is perhaps you could point me to another forum?

I'm teaching myself maths because I've never been very good with numbers yet I've always been interested in the concepts - it's bothered me!

Anway I'm starting from the begining and would like to know if there are simple ways to multiply large numbers.

I found a good method online for any pairs of two digit numbers (the cross multiply technique) and wondered if it could easily be extended to three and greater digit numbers. I couldn't get it to work!

Is there a quick way?

(Along the way though I found a quick method for finding the square of any number ending in 50 (not that useful, but there you go). The last four digits are always 2500 so then you simply square the number to the left of the '50' part and add itself to the prduct ie: (n^2)+n

so 450^2 is (4x4)+4 stuck on the left of the 2500 part = 202500

Seems to work for all the numbers I tried. I don't understand why though).

g