#it's like ad Infinitum don't even count in the line-up...

[maths-screaming]

A Hypothesis as to Why My 80s/90s K-12 Math Ed Sucked

K so today is "going down the line until someone has a spare set of tens they can loan you" subtraction. AKA problems like "300 - 214" or "4000 - 738."

As usual, I'm doing these with the unit blocks because the primary school textbook told me to:

I'm also doing these with the blocks because I am historically terrible at problems that involve multiple "borrow" steps. Specifically, I can never remember when to borrow and when not.

My fifth-grade teacher once told me I'd make "a terrible banker" because "you borrow too much money!" I think he meant this as a joke. As a kid, I felt weirdly insulted; as an adult and a teacher, I wonder why he didn't do a single thing to help me stop "borrowing too much."

That specific teacher aside (he was legit bad at most aspects of teaching), using unit cubes for multiple-borrow borrowing also has me wondering: Was 80s/90s math education bad because we thought we were imitating good math education?

When the Common Core standards first dropped, the Internet was awash in examples of number lines, "counting on," and other CPA-esque methods of teaching primary math. A lot of these examples got pushback from their posters, who didn't grasp that there are many ways of thinking about numbers.

A friend of mine, a marine biologist, replied: "What most people don't get is that these Common Core examples are how people who are good at math think about math."

(Said friend was very good at math and regularly surrounded by people who are good at math, so I believe her.)

When I was taught basic math, we were deprived of concrete manipulables and even pictorial representations almost immediately. If we demonstrated that we understood what a number symbol stood for (7 = "that's a seven" *holds up seven fingers*), we were deemed "too advanced" for concrete or pictorial representations.

By the time we got to the borrow-ad-infinitum-minus-one type subtraction, most of us had had concrete tools withheld for at least two years (first and second grade) and sometimes 4-5 years.

People who are good at math can look at a problem like 4000 - 1228 and get an accurate answer fairly quickly in their heads. There are no manipulables involved and there may be no jotting answers down, either.

I'm no historian of math education, but I wonder if the prevailing hypothesis was "if people good at math can do this invisibly, then to make kids good at math we should make them do it invisibly too, and as soon as possible."

Anyway I still suck at borrowing repeatedly, so back to the clicky blocks it is for me.

[tenrose]

Seriously who does this? Starting earlier than the announced schedule? We are in fucking France we start LATE 😤