Anyone know a good source for this?

I have MMM by martin gardner, and am looking at the principles of casting out nines.

I'd like to find a method for multiplying large numbers mentally.

All the best, Corona

Over at Grey Matters, I've linked to some great Mental Math Websites. Also, Harry Lorayne's upcoming Mathematical Wizardry book might have several things along this line.

For sources you can find in a regular bookstore, there's Math Magic by Scott Flansburg, Mathemagics by Arthur Benjamin, and Self-Working Number Magic by Karl Fulves.

More specifically, you may want to look at these tricks for multiplying two 3-digit numbers mentally, multiplying any numbers two numbers apart mentally, or some of the tricks over at MathPath.

Thank you scott you are a gem!

Corona

Thank you scott you are a gem!

Corona

If you get Mathemagics, you are in business. It is vastly superior to other books and web-based publications. There is a great chapter on mnemmonnics, and a chapter of ready-to-perform stunts; including cube root extractions of 6 digits numbers, magic squares, and instant additions of several 4 digits numbers. But ultimately, it is the legitimate mental calculations that you may be after, and Benjamin's method is coherent, consistent and fun (in a perverse way).

I just bought MATHEeMAGIC by Vale Heath. Is this a differnt book?

It is a different book slim,

Scot cram has kindly linked to it on amazon above,

I intend to get these books soon:

Mathemagics: How to Look Like a Genius Without Really Trying by Arthur Benjamin, Michael B. Shermer

Speed System of Basic Mathematics by Jakow Trachtenberg, et al

Speed Mathematics Using the Vedic System by Vali Nasser

Any thoughts on these?

I went through the algebraic porthole of scott's website (which is great by the way!)

Corona

Not on those books. I also just bought The Magical Math book by Bob Long and the Lorayne book is on order..Pre-Paid.
My Daughter, The Bean, just won the Math Challenge in her class yesterday. She will be taking on the rest of the school winners in a few days. She seems pretty confident although there are many students a year or so older.
I'm going to link her to Mr. Crams site. It's a good one. I learned THE KNIGHTS TOUR there last week.

I wonder why children are not taught these methods in schools.

The Bean is lucky to have a Dad whose on the case!

All the Best,

Corona

ps I have miniature knights tours in my wallet, just in case.

OK...Is it the same Matemagics that is on sale here?
http://cgi.ebay.com/Childrens-MATHeMAGIC......ViewItem
Book Video and audio?

http://www.amazon.com/gp/product/1565651......-1269631

Here it is Slim.

Are these the same book. Same name ..Same author????? Mine has audio and video too...????

Yes you are right slim my apologies, shouldn't judge a book by its cover etc

it is the same

phew!

You sure? LOL LOL LOL LOL

Unless that is a kiddies version.

(slightly embarrassed chuckle)

I must say Arthur Benjamin's book is excellent. I never passed Algebra and somehow got through our public education system years later I went back and magic and math tricks especially helped me though courses in college..also Persi Diaconis the mathe teacher at Standford is an excellent math-a-magician..