It is something like 198g isn't it? Not sure how many potatoes that equates too!
We always make sure we are on an EE day if we are planning and having meat and potatoes or meat and rice for an evening meal - however this is usually only a Friday night (fish and SW chips) or a Sunday (roast meat and roast potatoes).
198g is 7oz...I still work in old money! Lol...It varies on the potato size as to how many that comes to, so you would be better off investing in a cheap scales Hun.