(source: Jusco Pearl Megazine, Mar2009, Issue 47)
A phrasal verb combines a verb (action word) with a preposition and often it does not carry the same meaning as the original word. For example,"give up" is a phrasal verb that means "stop doing" something, which is very different from "give".
Now, one of the reasons English learners say that they find phrasal verbs difficult is that one phrasal verb can have several meanings. And work out is a very good example of this.
Let's say, Tim's got a new job, and one of his friends gives him support and encouragement by saying i'm sure you'll work out fine. Now in this context, work out means " to be effective, satisfactory or to have a good result".
But if you work out in the gym for an hour everyday, work out means "to take strenuous and systematic exercise.
Well, those are just two meanings, but work out has yet more meanings:
For example, it means " to discuss something in order to come to an agreement" , for example:
We've only been sharing the flat for a few days. We haven't worked out who's going to do which bits of housework yet.
And work out can also mean "to do a calculation"
I've added up all the household expenses and divided them between the three of us, and it works out at RM80 a month each.
And another meaning of work out means "solve a problem".
For example, if you're reading a newspaper in English and you've come across a word that you don't know the meaning of, you can read the sentance, look at the context in which the word appears, and through context you can solve yhe problem of the unknown meaning, you can work it out.
Learning phrasal verbs is probably a lifetime's work and if you want to do it well, it's probably worth getting hold of (=obtaining) or lashing out on (=spending a substantial sum of money on) a dictionary of current idiomatic English, which pays attention to verbs with prepositions and particles. I emphasise the word "current" as idioms come into and go out of fashion.