Topic: Fun with math[s]...anyone?
started by: waltre
Posted by waltre on Jul. 01 2002,00:01
Do any DetNetters know any fun mathematical methods, tricks for multiplying large numbers or interesting patterns they would like to share? This is a very geeky pastime for some, but it is a very handy tool to be able to multiply, add, square and divide numbers in your head using easy techniques. And a lot of the time, the only thing stopping people from being good with numbers (minus a calculator), big or large, is a technique or two that they find easy to work with.
Surely someone can share their techniques, something they learned from school or a good math[s] teacher.
If anyone is interested, i have put a page up, < my 'math[s] for wankers' page > at fortunecity, detailing some methods of squaring two digit numbers in your head.
And I'm sure there is some clever folk out there with some neat ways to crunch numbers without so much as a pen and paper.
Posted by Bob_the_Cannibal on Jul. 01 2002,00:35
quick pattern of multiplication by 9.X*9:
1| 2| 3| 4| 5| 6| 7| 8| 9|10
0| 1| 2| 3| 4| 5| 6| 7| 8| 9
9| 8| 7| 6| 5| 4| 3| 2| 1| 0
lame, yes, but it works for me.
also for factoring, if it's 2 digits, and the digits add to 9, then 9 is a factor:
54; 5+4=9, 9 and 6.
oddly, this trick helped for a problem on the ASVAB.
Posted by Necromancer on Jul. 01 2002,02:25
um times things by five can be made a bit easier by simply adding a 0 to the number and divding by two.(times by ten and half)
timesing indices is easy you just add the indices together.
all the other stuff i just use a calculator cos thats the smart thing to do.
Posted by forumwhore on Jul. 01 2002,02:28
Hot DAMN you know the plural of "index"!!!Now if we can just educate people that
"data" is plural....
(wait, "data" *are plural? Shaddup!
