Create some shapes by combining two or more rectangles. What can you say about the areas and perimeters of the shapes you can make?

Think of a number... follow the machine's instructions. I know what your number is! Can you explain how I know?

Think of a number and follow my instructions. Tell me your answer, and I'll tell you what you started with! Can you explain how I know?

Crosses can be drawn on number grids of various sizes. What do you notice when you add opposite ends?

My two digit number is special because adding the sum of its digits to the product of its digits gives me my original number. What could my number be?

A geometry lab crafted in a functional programming language. Ported to Flash from the original java at web.comlab.ox.ac.uk/geomlab

Write a Logo program, putting in variables, and see the effect when you change the variables.

Learn to write procedures and build them into Logo programs. Learn to use variables.