some questions about FTB mod pack

I just started minecraft and i heard that it's pretty cool and i just wanted to know if i download it can i play the normal minecraft again? and can i play it on single & multiplayer or just single or multi? and is it free?

if you download it you can play normal mc again. yes you can play both single and multiplayer. and its free but you need a minecraft premium account.:P

Ugghh why won't they update it past 1.2.5