It's pretty easy, take the example of this fraction...
What you do in here is that you note down the <em>factors</em> of 2 and 4 over here.
<u><em>Factors of 2 and 4:</em></u>
2 = 1, 2
4 = 1, 2, 4
Now, you see that the <em>GREATEST</em> Common Factor (GCF) over here is 2.
Now that we see the GCF of 2 and 4 is 2, what you do next is, you have to <u>divide 2 by 2 AND 4</u><u><em>. </em></u>When you do this, you will get your results. 2 = 1 and 4 = 2, now put this in the fraction form again, meaning switch 2 with 1, and 4 with 2 in the fractions...
So your simplified fraction is !