# Khan/khan-exercises

Issue #5950: Improve hints for simplifying fractions

1 parent 870e511 commit d8a4f39094a305267c578df0cb8202b97d5d8aae kd5bjo committed with marcia Nov 10, 2011
Showing with 13 additions and 7 deletions.
1. +13 −7 exercises/simplifying_fractions.html
 @@ -42,24 +42,30 @@

There are several ways to tackle this problem.

-

What is the GCD of NUM and DENOM?

+

What is the greatest common factor (GCD) of NUM and DENOM?

-

GCD(NUM, DENOM) = GCD

+

NUM = getPrimeFactorization( NUM ).join( "\\cdot" )
+ DENOM = getPrimeFactorization( DENOM ).join( "\\cdot" )

+ +

\mbox{GCD}(NUM, DENOM) = GCD_FACTORS.join( "\\cdot" ) = GCD

- \dfrac{NUM}{DENOM} + \dfrac{NUM}{DENOM} + = \dfrac{NUM / GCD \cdot GCD}{ DENOM / GCD\cdot GCD}

- = \dfrac{NUM / GCD \cdot GCD}{ DENOM / GCD\cdot GCD} + \hphantom{\dfrac{NUM}{DENOM}} + = \dfrac{NUM / GCD}{DENOM / GCD} \cdot \dfrac{GCD}{GCD}

- = \dfrac{NUM / GCD}{DENOM / GCD} \cdot \dfrac{GCD}{GCD} + \hphantom{\dfrac{NUM}{DENOM}} + = \dfrac{NUM / GCD}{DENOM / GCD} \cdot 1

-

- = \dfrac{NUM / GCD}{DENOM / GCD} + \hphantom{\dfrac{NUM}{DENOM}} + = \dfrac{NUM / GCD}{DENOM / GCD}

You can also solve this problem by repeatedly breaking the numerator and denominator into common factors.