I guess you want these in order of size. One way is to find the least common denominator =3*4*5=60.
Now express each fraction in 60ths: 45, 30, 36, 40. In order these are: 30, 36, 40, 45 which means that the range is from 30 to 45. 30 was the second fraction 1/2, and 45 was the first 3/4. So the range is 1/2 to 3/4.