How many pencils are there in half a dozen?
Half of a number, an amount, or an object is one of two equal parts that together make up the whole number, amount, or object. 一半
If you have a dozen things, you have twelve of them. 十二
The word dozen meaning a set of 12, comes from old French word dozeine (twelve) which was derived from the Latin word duodecim (meaning twelve).
Although, there are some weird terms like baker’s dozen, devil’s dozen, long dozen etc. which measure 13, one more than standard dozen value. In olden days bakers used to make one extra item for an intended dozen as an insurance against any item turning out to be faulty which could cause the baker to be fined. There are several theories as to why the bakers dozen value is 13 and not 12. For instance, in Egypt if a baker was found to cheat someone they would have their ear nailed to the door of their shop. Such strict laws made them take extra precaution in every possible manner.