Speed Mathematics by Bill Handley (2003, Paperback)

Bill Handley is an Aussie - yeah! I love this book, and have an admiration for his memory stuff too. "Speed Mathematics" has some neat little ideas to make you quicker, just in how you mentally process maths as well as some nifty things with 11 and other numbers. His actual "faster than a calculator" "trick" takes a little effort, but once you have it, it works. I am not someone with discipline, and unless I remind myself to recap the techniques, quickly forget. Handley also has most of his work on cassette as series (including improved memory, & learning languages.) If you enjoy maths or want to encourage your kids, the benefits to self-esteem (and more) are lucidly explained by Handley. It's worth grabbing a copy if you can. The latest edition is fabulous, but his earlier one is good too. If you google him you can find his website and other products. They do crop up on ebay. :)