How to get older Facebook version?

HI. So I was updating pinterest but it needed my moms apple ID and I didn't have it because I used hers when I first got my iPad, so I deleted it and was gonna get it again and I deleted my Facebook too because it also used her apple ID, so when I went to re download the apps it said it needed iOS 6.0 for pinterest and 7.0 for Facebook, but when I used my moms apple I'd when I first got my iPad it said I could get the older versions but now it won't. I really want Facebook and pinterest back. Can anyone tell me how?