Almost every mom is intimately familiar with the plaintive wail, “But, that's not fair!" Kids seem to come into this world knowing those dreaded words. This phrase is the go-to complaint anytime something doesn't go their way.

Mom won't let me eat cake for breakfast? Unfair!

Dad says I can't roll around in the dirt? Unfair!

I have to go to bed now? Definitely unfair!

If your tot hasn't discovered this phrase yet, pat yourself on the back for proactively planning for the inevitable tirades soon to come.

The protests of a child may seem a long way from the ivory tower ruminations of philosophers and mathematicians. It turns out, a particular area of study, known as game theory, can help shed light on how kids learn about fairness.

Game theory is the science of strategic thinking and if parents stand a chance of keeping up with their wily kids, it's exactly what they need.

Game theory started out in the 1940s as a theory of economic behavior. But since its invention, game theory has been applied to a wide variety of human endeavors, from international intrigue to family dynamics.

And game theory has a lot to say about fairness.Although kids are likely to call almost anything “unfair," these scholars have a more nuanced understanding of the term.

In the 1960s, a Columbia University professor, Sidney Morgenbesser, was arrested while at a protest. The police roughed up many of the protesters, including Morgenbesser.

When he was brought before a judge, the professor complained about his treatment. The judge asked Morgenbesser if he felt the physical violence was unfair. As an astute philosopher, Morgenbesser refused to call his treatment unfair because the police beat everyone; he said it was “unjust but not unfair."

Try explaining this one to your crying two-year-old. It's sure to work.

Okay, maybe not.

Other game theory ideas are ready-to-use for little ones. From a young age,kids have one notion of fairness that closely relates with envy. If young Suzie sees that Jamal got more time on the tablet than her, she's sure to be upset. Jamal got more, that's unfair!

Research from Peter Blake and Katherine McAuliffe found that kids as young as four were sensitive to this type of unfairness, but even younger kids can be, too!

There's another side to fairness: the unfairness of getting more than another. So, while Suzie is unhappy that Jamal got more than her, Jamal may not view it that way. He's content with all of his screen time. There's nothing unfair in his eyes—until he gets a little older.

Blake and McAuliffe found that older kids became sensitive to this more nuanced type of unfairness. These older children would be unhappy if they got a lot more than another child. They understood the receiving end of unfairness—even if they weren't the ones receiving it.

Sensitivity to this type of unfairness seems to set in around eight years. (Although, you may know a few adults who haven't yet reached this stage of development.) ?

An old parental standby can help parents teach their kids both sides of fairness. Many parents know to use “I cut, you pick" to divide cookies or cakes between fighting siblings or friends.

Jamal cuts the cookie in half and then offers the choice of halves to Suzie. Game theorists have shown mathematically that this should always lead to an “envy-free" division of the cookie.

If Jamal divides the cookie into unequal pieces, then Suzie will choose the larger. To see this, Jamal has to think from both sides—what is fair to me and what is fair to Suzie. When Jamal does, he cuts the cookie into equal pieces and neither child envies the other's share.

But this strategy doesn't need to be reserved for the rare sweet snack. Anything can be divided this way. Are your kids arguing about which toys they get to play with? Jamal can sort the toys into two piles and Suzie can pick the pile she prefers.

It may even solve a few tiffs between you and your partner! Trying to decide how to divide parental duties this weekend? Have your partner divide the tasks into two batches and select the one you like the most—or dislike the least.

Armed with a few classic game theory strategies, you stand a chance at producing a kid who not only knows when she's being treated unfairly but also sees the value in being kind to others.

For more ideas on parenting with game theory, check out The Game Theorist's Guide to Parenting by Paul Raeburn and Kevin Zollman.