WASHINGTON - Trying to figure out how to split a restaurant bill often puts math skills and friendships to a test.
Splitting a bill evenly doesn't take into account when one person has several extra drinks before dinner, orders an appetizer or orders the lobster.
A newly published patent filing shows Google has developed a system that calculates how much each person owes in a joint expenditure, and transfers money between their accounts.
A mobile app can't be far behind.
In its 2012 patent filing with the United States Patent and Trademark Office, which was recently made public, Google describes a scenario with which many can identify.
"Typically one of the group members will pay the bill out of convenience and expects to be paid back by the other group members," according to the filing.
"However, some group members may not pay back their entire share of the bill or may forget and not pay back their share at all."
The filing offers a hypothetical situation, in which four friends go on vacation in Miami.
"One of the days only three of the friends go eat lunch at a restaurant because Friend 4 is not hungry at the time. The bill for lunch is $60 and Friend 1 pays the bill," reads part of the what-if.
Users in the group would be able to challenge an expenditure, according to the filing.
After an agreement is reached, payment and settling-up can be done automatically, using secure payment accounts.
Diagram from filing for bill-sharing patent (U.S. Patent and Trademark Office)