Trouble with crochet stitch help?

Trying to do a Close Scallops crochet stitch and I can't get the foundation chain right. The book I have says: use a multiple of 5 sts + 3 (multiples of 6 sts + 1 for foundation chain). I want about 100 base chains in the foundation chain I'm trying to make a small baby blanket. So what number of base chains do I need 98 99 or maybe 100? I can't figure it out.