paging with for loop

I'm trying to figure out the formula on how to page a file:

And when page = 1 then what is called $startpage (not to be confused with the paging of the url) would start at 1.
And when page = 2 then what is called $startpage would be 101.
And when page = 3 then what is called $startpage would be 201.

$totalPages=722;
$url_page= $_GET['page'];//grabs the page from the URL. The rest I can't figure  out if it's right.
for($thisPage = 1; $thisPage <= $totalPages; $thisPage = $thisPage+100 ){
	$startpage = $thisPage;
}
$num_pages = 100;

PHP:

 

I couldnot understand,but u can try this,

like this
if(page==1)
$startpage=what u want;
else if(page==2)
$startpage=what u want;
else if(page==3)
$startpage=what u want;


more infor.............

 

I think I almost figured it out:

/*
$totalPages=722;
$url_page= $_GET['page'];
$num_pages = 100;
for($thisPage = 1; $thisPage <= $totalPages; $thisPage = $thisPage+$num_pages ){
	$startpage = $thisPage;
}
*/
$num_pages = 100;//is the number of html pages inserted in a database per minute because online servers can't do all at once
$totalPages=722;//is the total amount of pages of html that exist
$end_url_page= $totalPages/$num_pages;//is LAST page of this file's url. This file will repeat every minute due to the 1 minute rule for online servers with the extension?page=1, ?page=2...
$url_page= $_GET['page'];//is PRESENT page of this file's url.
$startpage = (($url_page - 1 ) * $num_pages) + 1;//is the present html page to be inserted in the database

PHP:

I tried to be as detailed as possible. If there are any more questions let me know thanks!

 

How do you make it so that if the url has no ?page=1 extension then there has to be an assumption that it is 1?
This didn't work:

if($_GET['page']==''){
	$url_page = 1;
	}else{
	$url_page = $_GET['page'];
	}

PHP: