A Baker´s Dozen
A baker’s dozen means thirteen pieces of something. A dozen (twelve) plus one more.
Hundreds of years ago, the English bakers cheated on their customers by baking lightweight, fluffy pieces of bread. The British parliament reacted angrily passing a law saying to bakers that if they continued with this situation, they would be severely reprimanded/punished. The bakers, in turn, responded by giving thirteen loaves of bread to any customer who asked for a dozen so as to tell the government, “We are giving off bread as a gift”.