Other one from the summaries: I don't see how $((${X} + ${Y})) ... is more recommendable than ... $(( X + Y )) for example. But well, guide style

Other one from the summaries: I don't see how $((${X} + ${Y})) ... is more recommendable than ... $(( X + Y )) for example. But well, guide styles are a good thing, and this one can help to many people "not used" to deal with shell scripts to follow some basics. Edit: and help to people used to it, on working in a team.