You are invited to Log in or Register a free Frihost Account!

Fraction Trick

Ircher
Tired of having to find a common denominator? Want a shortcut to adding, subtracting, or dividing fractions? I'll teach you how soon!

P.S.: Is it okay if I reserved posts?
Btw, when I said soon, I meant within a week or less time, not 2 days!!
CHAOS-THEORY
 Code: Tired of having to find a common denominator? Want a shortcut to adding, subtracting, or dividing fractions? I'll teach you how soon! P.S.: Is it okay if I reserve posts?
*
look whose back again (; u should post it directly, why would u have to reserve lol xD
btw i ll be waitin' for the trick
the_emissary
Whats taking so long? I remember my lecturer showing me something like this in college algebra but I'm too lazy to search for the information. I too patiently await your shortcut.
Ircher
This DOES NOT work for multiplying fractions.
First, you cross multiply (N1*D2 is on the left).
Next, looking @ the above, set it as Cross-Product 1 (operation) Cross-Product 2 over D1*D2.
Then Simplify; simple right, it'd be easier to show on paper, but here's an example to perhaps better illustrate it.

What is 2/3 - 1/4? Using my tactic, it would be this:

• Step 1: 2*4=8; 3*1=3 (Cross-Product 1;Cross-Product 2)
• Step 2: (8-3)/(3*4) (setup the fraction)

What about Mixed Fractions? Well, I'll get to that in a future post, just remember, it will NOT, emphasis on NOT work for multiplication; I also believe I'm the first to discover this, but I have no Actual proof, however, I've seen no one else who knew this. Plus this is to make uncommon denominators simpler; so there is no need at all to do this with multiplication anyway; just multiply straight across!

So what do you think? Great or useless?
lkglacier
I feel like this is more work than necessary. For me, personally, I'm one who prefers fractions over decimals/percents/etc, so doing the mental math is hardly a challenge to begin with. I would be too lazy to do all that cross multiply/divide shtuff. lol

I would instantly want to just go: 2/3=8/12 and 1/4=3/12 --> 5/12. bam.
Ircher
 lkglacier wrote: I feel like this is more work than necessary. For me, personally, I'm one who prefers fractions over decimals/percents/etc, so doing the mental math is hardly a challenge to begin with. I would be too lazy to do all that cross multiply/divide shtuff. lol I would instantly want to just go: 2/3=8/12 and 1/4=3/12 --> 5/12. bam.

Okay, I'd like to ay that that was an EASY, so you get it, example.
Here's a harder one:
What is 12/13 + 5/6? Using my tactic, it would be this:

• Step 1: 12*6 = 72; 13*5 = 65. (Cross-Product 1;Cross-Product 2)
• Step 2: (72+65)/(13*6) (setup the fraction)
• Step 3: 137/78 (Simplify to normal/improper fraction)
• Step 4: 137-78=130-80+17-8=50+9=59
1 59/78 (Simplify to Mixed Number)
• Step 5: 1 & 59/78 (Simplify til you get your answer!)

Hopefully this showed how much easier it is; if that fraction can be reduced further, pm me; I didn't use a calculator by the way for this problem or the last, so you can see its effectiveness!
Lastly, do NOT try to do this to multiply fractions, it will NOT work; try it if you like, but you'll find I'm right.

@Ikglacier - The reason that you found the normal way simpler was because it was a simple example; this example should show you how powerful it is; if you don't like it, then just stick with what you do like, I'm not forcing you to do anything, I just thought I'd share an easier way to add, subtract, and divide fractions with uncommon denominators.
This is not an original thought. I often do this, even though I don't think in exactly the same terms.
a/b + c/d = (a*d + c*b)/(b*d)

Fraction multiplication and division also have very simple rules.
(a/b) * (c/d) = (a*c)/(b*d)
(a/b) / (c/d) = (a/b) * (d/c) = (a*d)/(b*c)
Ircher
This is just the summary; I may give a complete one when i feel like it which isn't now!
To add or subtract; just do it seperately.

To divide, you must use improper fractions.