Straight and simple answers. I think this hits the mark. There are only a few ways to choose from. Another one left unmentioned, which is probably under investing is plainly buying bitcoins. In my country there are shops and even convenience stores where you can buy bitcoins equivalent to its buying price, which is, I think, slightly higher than it's selling price. From there you can use that purchased bitcoin in any means you want, whether you want to invest it, hold it, trade it, basically all the above-stated ways listed above. It should just be taken note that there are varying difficulties on how to earn bitcoins, some may also need third party programs or hardware before you can earn using them like trading, gambling and mining.