Remember, we want the lowest possible number, so we should start from this way. And that's exactly why I began labeling on this side of the chain of carbons. So since we have a methyl group, we have three methylhexane. And finally, the last example, like this one, also has symmetry down the middle. It doesn't matter if we begin here or here, 1234-1234. So we write four, but now we have not a methyl, but an ethyl, because we have two carbons.