Sue, we are trying to understand this ordering fractions from least to greatest, 1/2 3/4 4/6 . I don't understand about change the denominator to 12?

You need to find the smallest number that is divisible by 2, 4, and 6. That's 12 -- so the common denominator is 12.

Study this site for information about how to change to equivalent fractions.

http://www.mathsisfun.com/equivalent_fractions.html

1/2 = 6/12
3/4 = 9/12
4/6 = 8/12