Nita

I was looking at the Block of the Month patterns. I'd like to make a twin sized bed quilt using the Prairie Queen BOM pattern. My Secret Santa sent me five wonderful 1930's Reproduction FQs and I want to use them in the quilt. I'm trying to figure out how many more FQs I'll need to make this quilt (obviously, it will be a scrappy quilt). I'm hoping there is someone out there who is good at math that can help me out? Math calculations just boggle my little pea brain!
Thanks, Nita