I want to work out the return on an invstmt which involves an initial dep. then further deps AND withdrawals?

What I mean is, for example I deposit $100 in a savings account, then 2 months later withdraw $20, then 7 months later deposit $50 then finally withdraw $200 a year later. Whats the return on investment? All formulas I've come across dont allow for further deposits, they just allow for one initial deposit and a series of withdrawals.