Why the facebook app fot iphone is so slow and crashes all the time?

The only app that is slow in my iphone is the facebook app, doesn't matter how many times they update it, and is the one i use the most, and is frustating that is so slow to open a pic or to open a conversation, and just from nowhere it crashes and shut itself down, what can i do to fix this?

Added (1). I already deleted it and downloaded again, and i'm current with the updates, always

If this happens with any App, delete the App. Then download again and sign in.
Most of the time that fixes the problem.

If you haven't done updates to iTunes and Apps that messes things up.
Stay current on all updates.

Should this happen with almost any Iphone app, delete the particular Iphone app. After that obtain yet again and also sign in.
Usually in which treatments the problem.

I got a used iPhone from gamestop&still can't use it to update any apps because it says I don't have iOS 4, 5, or 6! What or how can I update my phone with apps&it also always shuts down when I'm reading or responding to my emails+ I've done everything to try to fix it& got Internet, minutes from net10&sims cards&went back to gamestop& got no Help! Please Help ME?! I don't want to hurt my sons feelings because he got it for me for mothers day&he's 12:) great son&great gift. Just wish it worked GREAT!