Explanation:
In mathematics, a rational number is any number that can be expressed
as the quotient or fraction a/b of two integers, with the denominator b not equal to zero. (Our solved example in mathguru.com uses this concept)
Since b may be equal to 1, every
integer is a rational number. The set of all rational numbers is
usually denoted by a boldface Q.
The decimal expansion of a rational number always
either terminates after finitely many digits or begins to repeat the same finite sequence of digits over and over.
Moreover, any repeating or terminating decimal represents a rational number.
http://en.wikipedia.org/wiki/Rational_number
Comparing fractions
Comparing fractions with the same denominator only requires
comparing the numerators.
\tfrac{2}{4}" *> because 3>2.
One way to compare fractions with different denominators is to
find a common denominator. To compare and, these are converted to and . Then bd is a common denominator and the numerators ad and bc
can be compared.
? gives \tfrac{3}{6}" *>
As a short cut, known as "cross multiplying", you can
just compare ad and bc, without computing the denominator.
?
Multiply 17 by 5 and multiply 18 by 4. Since 85 is greater than
72, \tfrac{4}{17}" *>(Our solved example in
mathguru.com uses this concept)
http://en.wikipedia.org/wiki/Fraction_(mathematics)
The above explanation is copied from
Wikipedia, the free encyclopedia and is remixed as allowed under the Creative
Commons Attribution- ShareAlike 3.0 Unported License.