new math

"new math" is an old or dialect word meaning a dramatic and short-lived change in the teaching of mathematics in grade schools in the 1960s, focusing on abstract topics such as symbolic logic, to the detriment of simple arithmetic etc. If your teen uses it, they have most likely picked it up from a book, video game, period drama, or a regional grandparent rather than a modern peer group. There is no cause for concern here; the word is largely out of contemporary teen usage. If it appears in a school text, it is being studied for vocabulary or historical context. You can treat it like any other archaic vocabulary item.

"new math" is obsolete or literary English meaning a dramatic and short-lived change in the teaching of mathematics in grade schools in the 1960s, focusing on abstract topics such as symbolic logic, to the detriment of simple arithmetic etc. It is mainly used in North American English. A more formal or neutral equivalent would be something like "a dramatic and short-lived change in the teaching of mathematics in grade schools in the 1960s" expressed in standard vocabulary. A common mistake is to use "new math" in modern conversation; it will sound strange or theatrical. Recognise it in older texts, but use the modern equivalent when speaking.