Me too! I thought I was so smart as a kid, realizing that stuff I didn't want to do was useless.

However, I was wrong. An over-dependence on calculators due to a lack of arithmetic fluency has sabotaged all my encounters with mathematics ever since. I had a hard time understanding and developing any kind of fluency because I was forced to push everything through a black box that also distracted me.

I now realize that memorized facts are the foundation for knowledge and advanced thinking. Dismissing memorization, especially of fundamental facts, is like choosing not to use RAM because you can always swap to disk.

Making it competitive between the two of the kids helps too... after all, sports is “just” being better at getting the ball in the goal better than the other team, right?

That said, I think your statement is absolutely incorrect in the context of higher math (and experimental science). The more facts you know -- whether literal facts, axioms, proofs, applied example or theories -- the more facile problem solving will be. This holds true in all disciplines (and not just math & hard sciences, but also engineering, social sciences & business).

A linear algebra course, on the other hand, is going to make mincemeat out of any student who can't do basic arithmetic in their head at high speed. Gaussian elimination, matrix multiplication, determinants, diagonalization; all of these tasks are extremely arithmetic-intensive. If someone needs a calculator to multiply 8x6 then they are not going to be able to solve a linear system in 4 unknowns on an exam that disallows calculators (which is all math courses at my university, besides stats and act sci).

IMHO, that's wrong in many cases. For instance: there's arithmetic in algebraic manipulations, and a lot of that is in the times-table memorization range. I definitely had to rely on my calculator in calculus class (and specifically swapped professors to one that would allow the use of one for that reason).

There's also the fact that neglecting memorization as a "waste of time" at the start of your math career sets up a bad precedent and bad habits that will continue throughout it, barring substantial corrective effort.

I, personally, only stopped having problems due to my deficit when I got to discrete math, which was the one math class I took that didn't involve numbers, like you said.

That's narrowing the argument I made, I said "harder problems", of which higher math is just one aspect.

Even sticking to just higher math; you're going straight from arithmetic to... calculus? What about algebra, trig, geometry; all much easier when your arithmetic chops are blazing?

(Which is what most people ought to be taking anyway instead of calculus.)

Additionally to your point, I think forcing arithmetic memorization on students is harmful because it makes math seem boring and hard.

But my point wasn't that it's foundation in general, category theory, set theory, etc are foundational, but that it's important to start from it. Just because something is foundational doesn't mean it's a good starting point.

> it doesn't mean you need to know an entire table.

Kids at an young age are usually very good at memorizing things and once they have memorized then they can build on that and learn new tricks, relationships, abstract and foundational principles.

> Not knowing 7x8 never held me back in higher math/math-relevant classes like Calculus I-III,

Neither did me either. Embarrassed to say, I had forgotten a lot of it. But I would have been struggling early on in the 4-9th grades if I didn't know how to add or multiply numbers then. I would have been wasting time on tests doing it the slow way, instead of thinking of more interesting problems.

So to summarized, yes, it is not foundational but it all depends on age, it's better to take advantage of what the brain already knows how to do well at that particular state in time.

> In fact I'm pretty sure mathematicians are notorious for poor arithmetic.

Could be but if they are poor they would be left behind in early grades and might never becomes the mathematicians they are. There is also a bit survivorship bias in the sense that if there mathematicians who are poor ar arithmetic, they'd stand out and become memorable, but those that are good are not noticeable because they are expected to be good with numbers.

Also, smart kids who hate memorizing are often really bad at languages. Which are mostly memorization; there is no way to derive the language from the first principles. But I guess if one's first language is English, this is not a big problem.

I get it: memorizing stuff doesn't signal how smart you are. But at some moment, the lack of factual knowledge is going to overcome the advantage of being smart. You will start making logically correct conclusions from factually wrong premises, and you will be proud that you didn't fill your brain with garbage.

Mandarin has 5 tones and having a keen ear to identify each tone and then recognizing it and memorizing it and matching sound to meaning is an enormous advantage.

Also...teaching music..to recognize diff sounds/tones..musical notes(Bach would do) also gives mandarain/language/math students an edge.

If you do common ones like 2, 3, 5, and squares, that already covers most of them and you only have 10 left to remember them all.

Being able to do mental arithmetic for small numbers is actually a very useful life skill. Sure, everyone has a calculator in their pocket these days (despite what my maths teacher told me), but that overhead of having to pull your phone out does slow you down.

But I don't believe that rote learning your times tables up to 12 is the way to do it. Mental arithmetic should be incorporated into the curriculum in a more integrated way. The problem is that school systems love testing and grading people. And it's quick and easy to grade people on their times tables by giving them a speed test to see how many equations they can complete in 5 minutes. You can say that little Jimbo is doing his times tables at a third grade level because he knows his 2, 3, 5 and 10 times tables. It's a terrible method of testing student progress though, I managed to get all the way to high school and was in the top stream class and never learned my times tables.

The actual concept of multiplication tables is an important concept for children to learn though, as it does help solidify fundamental mathematical concepts.

Tip is another thing. And I like to "min/max" grocery shopping so I typically do mental math when shopping to maximize things like grams of protein/$.

It's just a general life skill.

120 x 500 gives a much better approximation, and just needs you to know 12 x 5 = 60. Better still would be 125 x 460, which is 1/8 x 46 x 100000. That's within 3% of the true answer, and all it takes is quickly dividing 46 by 8.

It's very helpful to be on good terms with numbers less than about 100, which is why the multiplication table is taught. It's useful for reverse calculations (like 46 / 8) as well as forward ones. Decimal equivalents (1/8 = 0.125) are worth learning as well.

The key to being able to quickly approximate things is to populate your mind with memorized values. They work as landmarks (so the 7x8 example, in conjunction with the decimal equivalent of 1/8, means that you know almost immediately that, e.g. 55 x 125 is close to 7000).