Ok, i started classes a few days ago and we did something called Process Calculus. We're learning how to make/change the subject of the equation. I'm a bit confused on a few things. Say i have this: r - t * a/b = k (make "b" the subject, a/b being a fraction) Answer : r - t * a/b = k r * a/b = k + t a/b = k + t - r a = b(k + t - r) a/k+t-r = b Is that correct? When i was doing it in class i was moving the wrong unknown first and ended up doing crap most of the time. Any tips? You can also give me a question, i like to practice.