//index.php
$smarty = new Smarty; 

$smarty->assign('number', 23.5787446); 

$smarty->display('index.tpl'); 

//index.tpl: 

{$number} 

{$number|string_format:"%.2f"} 

{$number|string_format:"%d"} 

//OUTPUT: 

//23.5787446 

//23.58 

//24