well, 3/4 can be left as 3/4, and 1/2 is equal to 2/4. both fractions have the same denominator, 4. All you have to do, is find the least common factor (LCF) then you multiply the numerator by what ever you have to multiply your denominator to get this number.
Example
1/4=2/8
4x2=8 so 1x2=2
3/4 = 2/4
Common denominator would be 4 because both are common in the denominators place and both factors of 4!
