The old (but still good) Flash version: Math Trainer - Multiplication
You can make the "Addition" version work on Multiplication by clicking the "Multiply" tab at top.
I am working on a short video about Dimensions.
This is my script. Is it accurate? Does it convey the ideas well?
Hi! Let's learn about Dimensions
In Geometry we can have different dimensions.
Let us start with a point.
Can't see it? Well it has no size, so we will highlight it.
Now lets allow the point to move in one direction.
We get a line.
We need just one value to find a point on that line. So we have one dimension.
A line is one-dimensional.
Now lets allow the point to move in another direction. And we get a plane.
We need two values to find a point on that plane. So we have two dimensions. We call it 2D.
A 2D object is flat.
Circles, triangles, squares and more are two-dimensional.
We also call them plane shapes.
Now we let that point move in another completely different direction and we have three dimensions.
Spheres, cubes, cylinders and more are 3-dimensional.
We also call them solid shapes.
We can have more dimensions, but I can't draw them.
In Physics Time can be thought of as a dimension, but not in Geometry.