Rewrite rules to subfolder - .htaccess

Question

I have my website on a subfolder
/application
/application/php (all php files)
/application/view (my templates files)
/application/admin (my admin)
on my .htaccess i have this condiction to the main files
RewriteRule ^(.+)\/?([0-9]*)\/?$ application/php/index.php
my website work perfect
www.mysite.com/
now i want to rewrite rules for the admin folder
www.mysite.com/admin read /application/admin/
i tried something like this but dont work
RewriteRule admin/^(.+)\/?([0-9]*)\/?$ application/admin/index.php
My FUll .htaccess
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !^(.+)\.(css|js|xml|swf|flv|pdf)$
RewriteCond %{REQUEST_FILENAME} !^(.+)\.(jpg|jpeg|png|gif)$
RewriteCond %{REQUEST_FILENAME} !^(.+)\.(ttf|otf|eot|woff|svg)$
RewriteCond %{REQUEST_FILENAME} !cron.php
RewriteCond %{REQUEST_FILENAME} !/cache
RewriteCond %{REQUEST_FILENAME} !favicon.ico
RewriteCond %{REQUEST_FILENAME} !robots.txt
RewriteCond %{REQUEST_FILENAME} !ajax.php
RewriteCond %{REQUEST_FILENAME} !sitemap.xml
RewriteCond %{REQUEST_FILENAME} !/template/(.*)\.html
RewriteCond %{REQUEST_FILENAME} !/application/inc/OAuth(.*)\.php
RewriteRule ^(.+)\/?([0-9]*)\/?$ application/php/index.php
#RewriteRule admin/^(.+)\/?([0-9]*)\/?$ application/admin/index.php (not work)
<IfModule mod_expires.c>
<FilesMatch "\.(ico|gif|jpg|jpeg|png|js|css)$">
ExpiresActive On
ExpiresDefault "access plus 30 days"
FileETag None
</FilesMatch>
<FilesMatch "\.(xml|php)$">
ExpiresActive On
ExpiresDefault "access plus 5 minutes"
FileETag None
</FilesMatch>
</IfModule>

Answer 1

Have it this way:
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^admin/assets(?:/.*)?$ application/$0 [L]
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^admin(?:/.*)?$ application/admin/index.php [L]
RewriteCond %{REQUEST_FILENAME} !^(.+)\.(css|js|xml|swf|flv|pdf)$
RewriteCond %{REQUEST_FILENAME} !^(.+)\.(jpg|jpeg|png|gif)$
RewriteCond %{REQUEST_FILENAME} !^(.+)\.(ttf|otf|eot|woff|svg)$
RewriteCond %{REQUEST_FILENAME} !cron.php
RewriteCond %{REQUEST_FILENAME} !/cache
RewriteCond %{REQUEST_FILENAME} !favicon.ico
RewriteCond %{REQUEST_FILENAME} !robots.txt
RewriteCond %{REQUEST_FILENAME} !ajax.php
RewriteCond %{REQUEST_FILENAME} !sitemap.xml
RewriteCond %{REQUEST_FILENAME} !/template/(.*)\.html
RewriteCond %{REQUEST_FILENAME} !/application/inc/OAuth(.*)\.php
RewriteRule ^(.+)/?([0-9]*)/?$ application/php/index.php [L]