When "friends" split a check, advice needed on getting them to fair share

[NewtonMP2100]

.....there is always one in the group that eats/drinks more than their share.....if you are very close friends and it doesn't matter, let it go....

....if it bothers you, keep cash on hand when you go out (keep a lot of singles) and just leave your share [ w/tip ] on the table when it comes time to pay......

....some times there is one in the group that will help to calculate to the last cents what eachtperson owes but that person doesn't always exist......