how do you work out unlike fractions

do you want to add them or multiply or what?

Find common denominators.  Then change your numerator if needed.  Say...3/5+4/6=?

You need to find the least common denominator LCD.

The least common denominator for these is thirty.

Now we need to change numerator.

5*6=30.  3*6=18.  3/5=18/30

6*5=30   4*5=20    4/6=20/30

The add, subtract or whatever you need.