> Just like every other "innovation" in mathematics education since, up to and including Common Core
Have you actually looked into it? I was skeptical too, but then I saw they were trying to teach kids the way I do math. For example, what's 4001 - 3989. The old way would be to borrow and carry three times. But change question to 1+4000-3990+1 and the answer is perfectly simple. Kids I went to school with would literally write out 43-39 with 13-9 and 3-3. Maybe they're just dumb, but you don't have to be a whiz to use these techniques if someone shows you them.
I hope they're still doing some times table memorization.
The easy ways work for easy problems. But the harder ways work for all problems. I've used a lot of that shortcut math before it was allowed in class. I probably would have been better off just doing it the regular way, especially so I wouldn't get points off for not showing my work or showing the wrong work.
They don't have to "work" as in "be an efficient pen and paper algorithm", because the far more efficient algorithms is "use a computer"! They have to be good to build understanding and intuition, and e.g. presenting subtraction as "distance on the real line" is an excellent way to do this.
I did not expect this short-sighted way to look at maths education here in this website.
At least in the UK, where we also learned these sorts of arithmetic tricks, we still learned the "harder ways". The point of these techniques wasn't to replace long multiplication or something, but more as shortcuts so we didn't have to do it if we didn't need to, and we could simplify problems if we saw a better way to do them.
We also practiced this stuff regularly, and had mental maths quizzes at least once a week. And (at least when we weren't learning a specific technique), it didn't matter how we did the calculations, so if you felt more comfortable with the traditional methods, you could do that, you were usually just slower. (I was one of those slower people very often!)
The point isn't to go "here's how you do maths, it's always like this". It's about (a) helping you do arithmetic more quickly, and (b) helping you understand why numbers behave the way they do, in terms of bases and pairs and factors and other things like that.
Implementation is terrible though. The only explanation I have for the terrible tests given at my kids' schools is that they are to test the teachers not the students.
For example, the curriculum indicates a teacher must teach 4 strategies for multiplication. Totally reasonable. But then the test will have questions like "Perform this multiplication using strategy foo" which seems like putting the cart before the horse. Isn't the whole point of teaching multiple strategies is so that at least one sticks?
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And no, they aren't doing times (nor even addition) memorization in school. We did them at home and the benefits were absurd.
I’ve had three kids go through the early grades with it. I was on the fence at first. It turned out to be awful. The kids hate it. We hate it. There’s weird unhelpful bullshit vocabulary everywhere (“let’s use ‘number sentence’ in kindergarten before we’ve taught kids what a regular sentence is, that’ll surely help!”). Solving the same problem five ways which is infuriating to a kid who “gets it” already and has been very harmful to their opinion of school in general. Their deeper mathematical understanding doesn’t seem to be any more advanced than mine was in elementary school, which was supposed to be the point, and we’re having to supplement the “bad” stuff like multiplication tables so they’re not lacking the very most important math skills in every day life and needed to make actual progress on wrapping one’s head around even simple stuff like, say, algebra involving fractions.
Terrible, way worse than even my more-pessimistic guesses would have been.
Have you actually looked into it? I was skeptical too, but then I saw they were trying to teach kids the way I do math. For example, what's 4001 - 3989. The old way would be to borrow and carry three times. But change question to 1+4000-3990+1 and the answer is perfectly simple. Kids I went to school with would literally write out 43-39 with 13-9 and 3-3. Maybe they're just dumb, but you don't have to be a whiz to use these techniques if someone shows you them.
I hope they're still doing some times table memorization.