October 1st, 2007 in Miscellaneous
10 Math Tricks You Probably Don’t Know
No matter how hard you try, maybe giving up maths straight after leaving high school, you inevitably end up having to solve a bleeding problem some time.
Or you enjoy the simplistic logic of maths. Either way, these 10 easy tricks to solving a few harder problems will be of use to you.
The first trick is similar to the times 10 trick where you just add a zero to multiply anything by ten. This one is for multiplying by 11.
Take the original number and imagine a space between the two digits (in this example we will use 52: 5_2
Now add the two numbers together and put them in the middle: 5_(5+2)_2
That is it - you have the answer: 572.
10 Easy Arithmetic Tricks - [Listverse]
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Comments
Brandy says on October 1st, 2007 at 3:40 pm
Sweet!
Mathies says on October 2nd, 2007 at 6:45 am
Well, then try 55 or 66 or 77 for that great 11-rule.
Joe Freudenthal says on October 2nd, 2007 at 10:56 am
Doesn’t work for numbers such as 48, however, where the two digits added together are greater than 9. Right?
jim says on October 2nd, 2007 at 1:09 pm
in that case when the middle number goes into double figures, add it to the first number.
i.e. 49 x 11
4_(4+9)_9
which works out 4_(13)_9
so add the 4 and 13 = 53
and the 9 on the end = 539
catherine says on October 5th, 2007 at 10:42 pm
Maths doesn’t use ’simplistic’ logic. Simplistic doesn’t mean ’simple’, it means ‘treating complex issues as simpler than they really are.’
Apart from that - nice tip, and thanks Jim for the advanced tip!
thisispoo says on November 19th, 2007 at 12:58 am
dry who like maths anyway
gdr says on March 18th, 2009 at 3:52 pm
if for example I 895 x 11 or more digit numbers with how the trick is to multiply by 11?
Fred says on March 22nd, 2009 at 12:07 am
895 x 11 =
8950
+895=
9845