Eggs, flowers, and doughnuts are just some of the things that are often sold or grouped in sets of 12, also called “a dozen.” Because 12 is an easy number to divide into halves, thirds, and quarters, many companies sell everyday items like pencils and disposable cups by the dozen.
Mesopotamians from long ago were probably the first people to use 12 as a unit of measurement. The idea probably came about because each finger has three joints, which makes it possible to use the thumb to count to 12 on one hand.
In the ancient world, the number 12 also had a lot of meaning because there are about 12 lunar cycles in a year.
Items that come in sets of 12 can also be put together to make larger sets. This is a common way for manufacturers to sell items in bulk. A gross is equal to 12 dozens, while a great gross is equal to 12 gross.
A “baker’s dozen” is a set of 13 baked goods that are sometimes sold as a single unit. In the 13th century, if you tried to trick a customer, you could lose your hand. This is when the practise of giving an extra item started. So they wouldn’t lose a hand because of bad measuring, bakers put an extra piece in each dozen.