JavaScript | Flashes numbers for abacus or mental arithmetic practice |

php | Converts between base 10, base 20, and mayan calendrical numbers |

php | Uses the iterated method to approximate Julia sets and displays the equations for coloring them. |

JSXgraph | Shows the rate proportional to initial value property of simple interest |

JSXgraph | Construct an exponential function using the property that rate is proportional to the value of the function |

PHP | Properties of arithmetic as a puzzle game of two column proofs |

JavaScript | Practice drill for running the "I can do Quadratics in my head" routine. |

JSXGraph | Five points determine a conic. |

JSXGraph | Assemble up to four Bezier cubics into a picture, and see the resulting equations |

JSXGraph | A tool for showing how a Bezier Cubic is drawn. |

JSXGraph | Create the equation of a line from point (*a*,*b*) and slope *m*. |

JSXGraph | Create a line from a point, and the knowledge that every time you go over by Δ*x*, you go up *m* times as much. |

JSXGraph | A tool for looking at the graphical relationship between A, f(A), and g(f(a)). |

JSXGraph | A graphing tool for making discontinuous or continuous non-exponential solutions to f(x+1)=2f(x), f(0)=1. Drag the red point and keep its x coordinate within [0, 1). |

JSXGraph | A graphing tool for making continuous non-exponential solutions to f(x+1)=2f(x), f(0)=1. Drag the red point to and over the blue x's. |

JSXGraph | A graphing tool for making discontinuous or continuous non-linear solutions to f(x+1)=f(x)+2, f(0)=0. Drag the red point and keep its x coordinate within [0, 1). |

JSXGraph | A graphing tool for making continuous non-linear solutions to f(x+1)=f(x)+2, f(0)=0. Drag the red point to and over the blue x's. |

JSXGraph | A virtual rubberband model for doing multiplication with dilation. |

JSXGraph | A four row caeser cipher slide showing the underlying modular arithmetic. |

PNG | A mod 26 number wheel for numeric ciphering |

JSXGraph | A slide rule for constructing caesar ciphers |

JSXGraph | Your very own Javascript decoder ring |

JSXGraph | A simple tool for teaching that slope is a constant relationship between all pairs of points on a line. Both points can be manipulated to explore the constant relationship, or a single point can be fixed and the other point manipulated as a tool for deriving formulae. |

JSXGraph | The fingertool parametric plotter with axes set for trigonometric function plotting. |

JSXGraph | The fingertool parametric plotter in four quadrants. |

JSXGraph | A variation of the fingertool parametric plotter with the ability to set the initial coordinates numerically. |

Javascript | For making bifurcation diagrams: a simple javascript program a specified number of times, while hiding a specified number of iterations. |

JSXgraph | A 50 iteration cobwebber, with composition, for finding cycles. |

JSXgraph | A simple 26 iteration time series, with fields to change the function and the initial value. Should be sufficient for most uses. |

JSXgraph | A simple 26 iteration cobwebber & time series, with fields to change the function and the initial value. Should be sufficient for most uses. |

JSXgraph | A simple 50 iteration cobwebber, with fields to change the function and the initial value. For those situations where you want just a little more chaos. |

JSXgraph | A simple 25 iteration cobwebber, with fields to change the function and the initial value. Should be sufficient for most uses. |

QTmov | A moving showing how to use a rubber band number line to multiply an interval by 2 and multiply an interval by 1/2. Used to contrast multiplication from repeated addition (addition movie below). |

QTmov | A moving showing how to use a rubber band number line to add 2 and add -2 to an interval. |

QTmov | Two movies designed to help teachers see the difference between derivative as a limit of a sequence of points and derivative as a limit of sequence of functions. A companion to "Graphing a Derivative" below. |

JSXGraph | A interactive diagram to help students see the "sliding secant" meaning of derivative (Tall 1986; Thompson 1994) as a limit of a sequence of functions. |

JSXGraph | A set of five applets designed to help students learn a continuous image of slope that is more than just rise over run. |

JSXGraph | A buggy (still in development tool) for graphing parametrically on a multi-touch tablet. |

PDF | A worksheet designed to highlight the distinctions between six different modeling assumptions that all lead to exponential growth. Solutions available upon request. |

QTmov | A movie designed to be used with supporting discussion to help students think about how to draw the graph of the composition of two functions from their individual graphs. |