Question 571552
<pre>
a + {{{1/4}}} - {{{a/6}}}

Write a as {{{a/1}}}

{{{a/1}}} + {{{1/4}}} - {{{a/6}}}

The LCD is 12.

The denominator of {{{a/1}}} needs to be multiplied by 12 to become
the LCD of 12, so multiply the first fraction by {{{red((12)/(12))}}}

{{{a/1}}}{{{red((12)/(12))}}} + {{{1/4}}} - {{{a/6}}}

The denominator of {{{1/4}}} needs to be multiplied by 3 to become
the LCD of 12, so multiply the second fraction by {{{red((3)/(3))}}}

{{{a/1}}}{{{red(12/12)}}} + {{{1/4}}}{{{red((3)/(3))}}} - {{{a/6}}}

The denominator of {{{a/6}}} needs to be multiplied by 2 to become
the LCD of 12, so multiply the third fraction by {{{red((2)/(2))}}}

{{{a/1}}}{{{red((12)/(12))}}} + {{{1/4}}}{{{red((3)/(3))}}} - {{{a/6}}}{{{red((2)/(2))}}}

Multiply the numerators and the denominators in each of the the three
terms:

{{{(12a)/12}}} + {{{3/12}}} - {{{2a/12}}}

Now that all three fractions have the same denominator, we combine
the three numerators and write that over the LCD of 12:

{{{(12a+3-2a)/12}}}


Combine the like terms 12a and -2a and get 10a.

So the final simplification is

{{{(10a+3)/12}}}

Edwin</pre>