Academic questions...

Satya

Satya

C'est la vie
Retired Staff
MBTI
INXP
Without a calculator, is there a faster way to reduce fractions than by factoring?
 
use a shredder
 
I just don't reduce them, if I can get away with it. If I know how to come up with the answer, then whoever is looking at the result can reduce their own damn fraction if they're that particular
 
Well, there are a few:

Even numbers can be factored by two.
If you add both digits together and that number is divisible by three, then the original number is divisible by three (63 --> 6+3=9 --> 63 is divisible by three)
I forget the rule to four, but that's okay cuz I never check for four anyways.
If the number ends in a 5 or 0, it is divisible by five.
If a number is divisible by both two and three, then it is divisible by six.
 
gloomy-optimist said:
Well, there are a few:

Even numbers can be factored by two.
If you add both digits together and that number is divisible by three, then the original number is divisible by three (63 --> 6+3=9 --> 63 is divisible by three)
I forget the rule to four, but that's okay cuz I never check for four anyways.
If the number ends in a 5 or 0, it is divisible by five.
If a number is divisible by both two and three, then it is divisible by six.
Click to expand...

Wow, I did not know the tricks for the second and last one. It feels like my elementary education was seriously lacking in the math department. I wonder what the trick for 4 is.
 
You don't really need a trick for 4. If it's divisable by 4 just use 2, since they're both even.
 
^^ That's what I always do. There's really not much point in checking.

There is a pattern with four, like all the other numbers, that's not too hard to figure out:
4, 8, 12, 16, 20 || 24, 28, 32, 36, 40...
ends in: 4, 8, 2, 6, 0 || 4, 8, 2, 6, 0...
So if it's divisible by four, it would end in one of those numbers, in increments of 20
 
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