RewriteRule does not work with leading / in pattern url or target url

I am using Ampps on mac, I see if I place forwarding slash either in patternurl or in target url , in any case it does not work

#no 404 error with below line if there is no forwarding slash with any pattern
RewriteRule ^main/(.*)$ index.php?term=$1 [L]
#but 404 error with any of these two
RewriteRule ^main/(.*)$ /index.php?term=$1 [L]
RewriteRule ^/main/(.*)$ index.php?term=$1 [L]
#and more surprise, if I place any forwarding slash in any pattern but use "RewriteBase /" does not work in this case too , below with error:
RewriteBase /
RewriteRule ^main/(.*)$ index.php?term=$1 [L]


though I found lot of examples over internet using forwarding slashes , I do not know whats going wrong , but again I am surprised when I run wordpress on localserver (AMPPS) , I check its htaccess file as below:


RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]

I see /index.php works here (there is no 404 error at all), what I am doing wrong.