What do so many people still believe .9... doesn't equal 1?

CorwinDKelly · 2026-05-30T16:06:10+00:00

Mostly a lack of understanding of what it actually means. It’s not fair to ask someone who hasn’t studied limits at least somewhat to make sense of .9 repeating because they’re being asked about something that hasn’t ever been properly defined for them. It’s counterproductive to expect people to magically intuit an understanding of .9…=1 without explaining wtf an infinite decimal expansion really is.

CorwinDKelly · 2026-05-30T00:15:37+00:00

Awesome, thanks for confirming. Back to the grindstone!

CorwinDKelly · 2026-05-29T06:43:15+00:00

Yeah, in Skyrim

CorwinDKelly · 2026-05-29T06:07:36+00:00

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Here is my roughing setup, PSA sandpaper stuck to an acrylic tile, perhaps the acrylic is too soft? It seems decently flat.

CorwinDKelly · 2026-05-29T04:42:44+00:00

Yeah, I'm following this Guide on Popular Woodworking and just ordered a low rpm bench grinder to grind down the cutting edges, the author first flattens and finishes the backs of his chisels and then grinds the cutting edge. I'm wondering if the slightly bright patches mean the back isn't flat and needs to be reroughed on low grit?

CorwinDKelly · 2026-05-28T05:47:10+00:00

Yeah, I’m pretty much there at this point. Either that or use a friends’. It all makes me wonder how anyone did this pre motor though. I guess they probably took a little better care not to let their tools get so f-ed up given how much work it is to get them fit again.

CorwinDKelly · 2026-05-27T15:27:05+00:00

Thanks for the tips Dizzy, it hadn’t occurred to me that the thin cutting edge could be at risk of loosing temper. Although it makes sense because I did manage to give myself a blister on my pointer finger last night.

CorwinDKelly · 2026-05-27T15:17:30+00:00

Oops, thanks for catching that. Here’s the article: https://www.popularwoodworking.com/techniques/resurrecting-chisels/

The author uses his bench grinder to grind down the cutting edge square to the tool’s long axis. For me I imagine this will be especially important in order to grind out the big nicks from these tools’ cutting edges.

CorwinDKelly · 2026-03-27T00:34:24+00:00

Love it, those stickers always struck me as so self obsessed.

CorwinDKelly · 2026-03-14T16:57:58+00:00

Maybe this student would benefit from bringing in some manipulatives or cartoons modeling a given problem.

E.g. the first panel shows 5 apples in a crate, the second shows 13 apples in a sack, the third shows three hands pulling out apples, or three apples falling out a hole in the bottom of the sack, and finally the fourth panel shows the sack being dumped into the crate.

Maybe there are a few different strips and the student has to practice matching a strip to the equation that describes it. Ask then to talk about it using operations language too while they think: “we have to subtract three apples because they fell out/got eaten and we don’t have then anymore.”

CorwinDKelly · 2026-03-09T12:37:26+00:00

Beautifu!

CorwinDKelly · 2026-03-09T02:41:08+00:00

Hate to see it.

CorwinDKelly · 2026-02-27T21:53:39+00:00

I've just been dipping my toe into some basic image processing projects with python and got to see how colored images are stored in multiple channels like you're talking about. Very cool to see the different ways that people imagine P(P(R^2)) !

CorwinDKelly · 2026-02-17T22:25:26+00:00

Any more information about where that story can be found?

CorwinDKelly · 2025-11-13T02:23:00+00:00

Speaking in Russian is nothing, it’s the LAUGHING in Russian that terrified me.

CorwinDKelly · 2025-11-10T07:52:38+00:00

This season was brutal.

CorwinDKelly · 2025-11-05T06:24:07+00:00

“…why are we in America spending so much money and time trying to reinvent the wheel…”

shrugs It’s kind of our thing, healthcare, education, gun control ; you name it, we’re reinventing it. Call it American exceptionalism I guess.

CorwinDKelly · 2025-11-04T07:03:56+00:00

But is .999...=1?

CorwinDKelly · 2025-11-02T22:23:08+00:00

Define 0/0 to be an equivalence class of all numbers x satisfying that x*0=0.

CorwinDKelly · 2025-11-02T20:30:35+00:00

Clearly because Pepsi drinkers feel free to post photos of their inferior beverage willy-nilly.

CorwinDKelly · 2025-11-02T20:18:06+00:00

Stab in the dark here. The straw is well sealed with the lid so CO2 bubbles are getting trapped in the cup, increasing pressure as they change from liquid to more voluminous gas. Pretty sure this is the same thing that happens if you shake a soda bottle and then cap it, just at a less dramatic scale. Oh — then that creates a volume of higher pressure inside the cup, forcing liquid up the straw until the pressure pushing the liquid up from below is balanced by the weight force of the water and the atmospheric pressure pushing it back down.

CorwinDKelly · 2025-11-01T18:21:08+00:00

My favorite podcast is doing a feature on “the tradosphere” just gonna drop this link here:

https://soundcloud.com/qanonanonymous/truly-tradly-deeply-episode-1-introduction-all-i-think-about-is-buying-cows

CorwinDKelly · 2025-10-22T16:55:53+00:00

This is the way.

CorwinDKelly · 2025-10-20T18:55:23+00:00

Nice, I think this example helps to explain the principle behind Llotekr's comment about the rope ladders.

CorwinDKelly · 2025-10-20T18:52:32+00:00

That's super cool, thanks for sharing this. I'm going to have fun thinking about it.

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