What is the actual definition of a quantagory?

Question

This is my son's Year 5 homework question. And how would he go about creating his own quantagorys?

Answer 1

Its a puzzle that is made with numbers and letters
example
Question
26 = L in the A

Answer
26 = Letters in the Alphabet.

Answer 2

"Nu metal is a controversial subgenre of alternative rock. It sometimes bears some influence from hip-hop, because rhythmic innovation and syncopation are primary. Nu metal bands also feature aggressive vocals (either rapped, shouted, or sung), drop-tuned guitars that are clean or distorted, (with riffing similar to the Seattle scene of the early 1990's) a funk-based rhythm section, and occassional DJ techniques such as turntables and sampling. Generally speaking, the emphasis is on either communicating feelings of angst and hostility, or motivating a crowd to move with the beat -- ideally, both at once." Basicly its hard rock with a bunch of other influences

Answer 3

They seem to be some sort of math and/or word puzzle that goes under various names. See the sites below for info.