The first three courses, and starting on Geometry

Hello, and welcome if you're new here.

Polymathy doesn't change much on the surface from one week to the next, and I know that can make a site look abandoned. It isn't. I work on it every day, and I thought I'd start writing a little about what I'm doing, so there's somewhere to check.

Right now

Three courses are open: Pre-Algebra, Basic Algebra, and Foundations of Mathematics. There are around 7,100 exercises between them.

Most of my time goes into those three at the moment. They need to be right before I add more, so I've been working through them properly, article by article and exercise by exercise. Close to a hundred small corrections in the past week alone. Little of that shows up on screen, but a course you can't quite trust isn't much use to anyone.

Geometry has already started, though.

If something looks wrong

Tell me. That goes for exercises that are plainly wrong, and for ones that are just confusing. The fault is often mine.

There's a feedback form in your account menu, and a link to the exercise is enough. Once you've completed ten exercises you'll also get a Flag button on every exercise page, which is quicker still.

You don't have to start at the beginning

Pre-Algebra starts from the very beginning, with arithmetic and fractions. That's on purpose. It means anyone can join and start at their own level.

But if all of that is well behind you, you're not stuck working through it. Open a course that's still locked, Basic Algebra or Foundations of Mathematics, and you'll see its prerequisites listed, each with a Test out button beside it. Six questions. Get five right first time and the course opens.

So take a look further along the map before you begin. There's no sense covering ground you already know.

New widgets

I've added three new widgets, mostly for the arithmetic and fractions material.

Vertical Arithmetic sets a sum out in columns and you type the digits into the blanks, including the carries.

Shaded Grid is a grid you click to shade, for fractions and percentages.

Area Model draws multiplication and factoring as a rectangle and you fill in the cells.

They're going into the first three courses as I work through them.

Next: Geometry

I've started building Geometry, and I'm quite excited about it.

Geometry suits this format better than almost anything else. So much of it is visual, and an exercise can let you drag a point and watch what happens. The tools for that are built and waiting.

It'll cover what you'd meet in a school geometry course, and then keep going a fair way past it. Compass and straightedge constructions get proper space. And the last part steps away from calculation altogether to ask what geometry is built on, and what happens if you change one of the assumptions: geometry on a sphere, where a triangle's angles add up to more than 180 degrees, and in a city where distance is measured along the streets.

Thanks for being here.