Good point. a 16-bit number can address up to 64Kb of memory, but doesn’t take 64kb of room. I’ll clarify.
[…] For a few more time-saving math tricks, check out this post at betterexplained.com. Here you can find some quick tips for calculating money and finance, as well as other estimates that can be helpful in daily life. […]
Kalid, great site! In your derivation for work hours, the third line should read:
days per year = weeks * days
Cheers!
PS Perhaps, in a future article you might be inclined to explain UNIX load averages (and different kinds of averages in general, like here)?
Hi Marc, thanks for comment & catch – should be fixed now! That’s a good topic suggestion, I didn’t realize there could be so many intricacies in a “simple” performance metric 
The last paragraphs discussing 2^10, 2^20, etc, may be a good place to introduce the concept of KiB, MiB, GiB nomenclature, (http://en.wikipedia.org/wiki/Kibibyte)
Hi, thanks for the suggestion. I think I’ll put in a link for the “new” notation.
could you do fraction and other end of the year work for math in 1 secondary
i love you
[…] Mental Math Shortcuts | BetterExplained (tags: math tips shortcuts mathematics howto maths lifehacks brain hacks) […]
Here’s one:
If you are looking to purchase a car and want to quickly assess what the monthly payment on a regular purchase (not a lease) will cost you, do the following. Take the bottom line (price + tax, title, license), multiply by 2 and chop off 2 places. Example: You want to finance a 25000 car (remember, this is after sales tax). Monthly payment is ~$500/month. See? Now, this does assume 60 months at 8% interest, but these are typical.
How to calculate x^y manually, is there any short cuts?
@Michael: Cool, thanks for the tip, it’s a nice rule of thumb. It’d be neat if there was a way to account for different terms/interest rates too.
@Raj: There’s shortcuts above for powers of 2, but otherwise I think you’d need to just multiply it out.
How do you find multiples of 1-12 easily like if u add the digits of the number and it is a multiple of 3 the number is a multiple of 3?
do anyone knows shortcuts for solving number systems i.e. octal, binary please mail me at agarwalsagar@ymail.com
thanks for info. its raly usefull to students and staff
Thanks saravanan.
Great explained. congrulation you have to be really mathematician
Thanks Ales!
What’s 43% of 200? Same as 200% of 43: 86.
Nice