I daren't have 25g open and near me or else they'd all be demolished!! Unfortunately I work for the company who make Pringles so it's a very tempting environment to be in!!
you get about 15/16 in 25g
so if I go by 16 it's
16 = 6.5 syns
8 = 3.25 syns round up to 3.5 syns
4 = 1.6 syns round up to 2 syns
2 = 0.8 syns round up to 1 syns
1 = 0.4 syns round up to 1/2 syns
that's how I would do it in my head.. better check just be safe