The currency bid/ask quote for EUR/USD is 1.3602/1.3605 and you want to buy
the pair because you think the Euro is going to gain on the U.S. dollar.
So you buy 100.000 Euros (1 standard lot) for $136.050 US dollars (100.000 x
1.3605). At 100:1 leverage, you initial margin deposit would be $1.361 for this
trade.
Sure enough the Euro pair goes up and is now trading at 1.3665/1.3668 and you
decide to sell and take profits.
You would sell 100.000 Euros (1 standard lot) for 136.650 US dollar (100.000 x
1.3665).
Since you bought 100.000 Euros for $136.050 and sold them for $136.650, you
made a profit of $600 or 60 pips.
If on the other hand the Euro pair went down to 1.3575/1.3578 and you sold at
1.3575, you would have a loss of $300 (136.050-135.750).
If the account equity fell below the margin requirement, the trade would be
automatically liquidated.
With that background, I want you to stop right there. It seems like a lot of arithmetic, but it is very simple, really. You just look at the fact that you bought at 1.3605, and you sold at 1.3665 (first case example). The difference is 60 pips, and you know that for the EUR/USD pair, each pip for one standard lot is worth ten dollars, so 60 times ten is $600. It is that simple.