im a beginner and i hve what probably a simple question I would like to know. If I do not buy a whole coin. and say I buy 40 dollars worth, or into a coin. how do I calculate the profit I make as coin rises. As I said I am beginner but i want to figure out how to get in the concurrency market.
any help would be a blessing i just want to buy some coins and maybe send my son to college one day. thanks
The cryptocurrency market isn't special, things work the same as they would in any other market.  

It makes no difference how much you buy, nor what you buy (ie, bitcoin, an altcoin, Euros, a house, whatever).  Your profit is how much you sell for minus how much you invested.  So if you buy $40 worth of bitcoin, and sell for $50, you've made $10 profit (minus taxes and fees).