A dozen is twelve, a gross is one hundred forty-four, and both remain common in wholesale counting.

The longer version

Twelve divides cleanly by two, three, four, and six, so a tray of twelve can be split into halves, thirds, quarters, or sixths without leftovers. A gross stacks twelve of those trays, giving one hundred forty-four, which shares the same convenient divisors and packs naturally into a rectangular crate.

Market traders settled on these counts long before modern packaging, because halving and thirding mattered more than matching the number of fingers. Eggs, buttons, and pencils still arrive this way. A baker's dozen of thirteen has a separate story, usually told as an extra item added to avoid shortchanging a customer.

Where this entry sits

This section collects odd corners of mathematics, from stubborn prime numbers to counting systems older than modern schools. Expect famous constants, probability puzzles, shapes that break everyday intuition, and numbers far too large to picture. The full list sits on the Numbers and Math page, where every entry is listed in order.