# Just multiplied a 10 digit number by 12 in my head!!!!!

This really is quite amazing, don’t worry it’s not about me showing off. I’ve just started reading a book called the Trachtenberg System of Speed Mathematics (Amazon Link*). I found it on my father’s bookshelf when I was sixteen, but never read it properly. I picked it up again, and it’s incredible – and while I sound like one of the newspaper adverts for ‘enhance your memory’ products, put some work into this and the results are great.

The first thing it teaches is how to multiply any number, no matter how long (say 30 digits) by any number from one to 12. Once you know what you’re doing it just takes a few seconds to do, so you can see the number written down in front of you and by following a simple process do the multiplication there and then, without a calculator.

Then it gets much better – how to do long multiplication in your head. I started on two digits by two digits and am now starting (sometimes incorrectly) to do three digit times three digit multiplications (e.g. 922 x 443) in my head. It takes some unlearning and re-learning maths to do it, yet it’s easy to pick up very quickly. In many ways it’s more of a test of memory than maths.

Now you may be thinking “what a sad nerd??? and indeed you’d probably be right. However, if you enjoy doing Sudoko, I suspect you’d enjoy this too – and it has practical usage too. Well worth it. Grab it from the library.

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