Notice that there is an underscore after each 3 numbers, where a comma would usually be. The significance of the underscore is just a substitute for the comma in an unquoted string. Don't get worked up about it. It is just a visual convenience because it helps you distinguish between 700 million and 70 million by just counting the underscores.

Almost a Perl hacker.
Dave AKA damian
I encourage you to email me