Josh
(Josh Cohen)
1
This thread is for compiling the different systems of mental math as well as books and training tools.
I’ll link to pages about some of the methods I’ve heard of:
https://en.wikibooks.org/wiki/Mental_Math
Practice sites:
Post links if you know of any good information on the subject. 
1 Like
geezer
2
Here is a good practice site:
http://www.momonix.com/calc/
Dale
3