Comments on: Simple tricks for doing arithmetic in your head http://www.geeksaresexy.net/2008/02/19/simple-tricks-for-doing-arithmetic-in-your-head/ tech, science, news and social issues for geeks Fri, 21 Nov 2008 09:55:14 +0000 http://wordpress.org/?v=2.6.3 By: Chip http://www.geeksaresexy.net/2008/02/19/simple-tricks-for-doing-arithmetic-in-your-head/#comment-67005 Chip Wed, 07 May 2008 17:38:34 +0000 http://www.geeksaresexy.net/2008/02/19/simple-tricks-for-doing-arithmetic-in-your-head/#comment-67005 Good stuff, Stu! Thanks. Good stuff, Stu! Thanks.

]]> By: Stu Savory http://www.geeksaresexy.net/2008/02/19/simple-tricks-for-doing-arithmetic-in-your-head/#comment-66931 Stu Savory Wed, 07 May 2008 09:22:08 +0000 http://www.geeksaresexy.net/2008/02/19/simple-tricks-for-doing-arithmetic-in-your-head/#comment-66931 And I can also show you how to take cube roots in your head too. See http://home.egge.net/~savory//blog_feb_08.htm#20080229 And I can also show you how to take cube roots in your head too. See
http://home.egge.net/~savory//blog_feb_08.htm#20080229

]]> By: Stu Savory http://www.geeksaresexy.net/2008/02/19/simple-tricks-for-doing-arithmetic-in-your-head/#comment-66673 Stu Savory Tue, 06 May 2008 16:06:58 +0000 http://www.geeksaresexy.net/2008/02/19/simple-tricks-for-doing-arithmetic-in-your-head/#comment-66673 Hi Geeks, I have the tests for divisibility by all primes below 50 up on my website. Go look at http://www.savory.de/maths1.htm Hi Geeks,
I have the tests for divisibility by all primes below 50 up on my website.

Go look at http://www.savory.de/maths1.htm

]]> By: Neat math tricks: Integer divisibility | An Obvious Hack http://www.geeksaresexy.net/2008/02/19/simple-tricks-for-doing-arithmetic-in-your-head/#comment-47604 Neat math tricks: Integer divisibility | An Obvious Hack Thu, 21 Feb 2008 16:07:13 +0000 http://www.geeksaresexy.net/2008/02/19/simple-tricks-for-doing-arithmetic-in-your-head/#comment-47604 [...] ran into a really neat blog entry today when I was… well, looking for neat blog entries. You might’ve learned in [...] [...] ran into a really neat blog entry today when I was… well, looking for neat blog entries. You might’ve learned in [...]

]]> By: Chip http://www.geeksaresexy.net/2008/02/19/simple-tricks-for-doing-arithmetic-in-your-head/#comment-47441 Chip Thu, 21 Feb 2008 01:37:49 +0000 http://www.geeksaresexy.net/2008/02/19/simple-tricks-for-doing-arithmetic-in-your-head/#comment-47441 Not a problem. Thanks for reading and commenting! Not a problem. Thanks for reading and commenting!

]]> By: Awangku Yusli http://www.geeksaresexy.net/2008/02/19/simple-tricks-for-doing-arithmetic-in-your-head/#comment-47439 Awangku Yusli Thu, 21 Feb 2008 01:33:51 +0000 http://www.geeksaresexy.net/2008/02/19/simple-tricks-for-doing-arithmetic-in-your-head/#comment-47439 Ah yess... my mistake. Stupidly, I did not click the link to the 10 tricks. Okay, I'm embarrassed now. Hahahahaha... Ah yess… my mistake. Stupidly, I did not click the link to the 10 tricks. Okay, I’m embarrassed now. Hahahahaha…

]]> By: Chip http://www.geeksaresexy.net/2008/02/19/simple-tricks-for-doing-arithmetic-in-your-head/#comment-47409 Chip Wed, 20 Feb 2008 22:01:19 +0000 http://www.geeksaresexy.net/2008/02/19/simple-tricks-for-doing-arithmetic-in-your-head/#comment-47409 Thanks, Awangku. That's actually #2 in the post linked to above. Thanks, Awangku. That’s actually #2 in the post linked to above.

]]> By: links for 2008-02-20 -- Chip’s Quips http://www.geeksaresexy.net/2008/02/19/simple-tricks-for-doing-arithmetic-in-your-head/#comment-47266 links for 2008-02-20 -- Chip’s Quips Wed, 20 Feb 2008 08:27:16 +0000 http://www.geeksaresexy.net/2008/02/19/simple-tricks-for-doing-arithmetic-in-your-head/#comment-47266 [...] Simple tricks for doing arithmetic in your head Have at it, Stu! (tags: arithmetic tips hacks) [...] [...] Simple tricks for doing arithmetic in your head Have at it, Stu! (tags: arithmetic tips hacks) [...]

]]> By: Awangku Yusli http://www.geeksaresexy.net/2008/02/19/simple-tricks-for-doing-arithmetic-in-your-head/#comment-47237 Awangku Yusli Wed, 20 Feb 2008 05:59:09 +0000 http://www.geeksaresexy.net/2008/02/19/simple-tricks-for-doing-arithmetic-in-your-head/#comment-47237 A quick way to calculate the square of a number that ends with a 5. Example: 65 x 65 1. Add 1 to the first 6, equals 7. 2. Multiply this 7 with the second 6, equals 42. 3. The last 2 digits will always be 25. 4. So the answer is 4225. A quick way to calculate the square of a number that ends with a 5.

Example: 65 x 65

1. Add 1 to the first 6, equals 7.
2. Multiply this 7 with the second 6, equals 42.
3. The last 2 digits will always be 25.
4. So the answer is 4225.

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