Most are in GeoGebra, which should run on any computer. We are in the process of updating these to run withough java; updated applets have a *.
Most coordinate with the curriculum Measuring the World: Mathematics for Elementary and Middle School Teachers.
Elementary mathematics
Arithmetic
Place value
Base blocks (any base up to 10) with 6 place values *
Addition and subtraction
A slide rule for adding and subtracting
Multiplication
The Frog Stretcher: multiplication as scaling
The Frog Stretcher for fractions: multiplication as scaling
The Stack Stretcher for integers: multiplication as scaling
The area model for multiplying whole numbers
The area model for multiplying fractions
Multiplication and division
Daisy chains: arrow diagrams for multiplying and dividing fractions
A slide rule for multiplying and divding
Ratio, proportion, percent
Strip diagrams for percent
Geometry
Polygons
What is a rectangle?
What is a parallelogram?
What is a rhombus?
What is a trapezoid?
What is a kite?
The height of a parallelogram with fixed side lengths
The side lengths of a parallelogram with fixed height
The area of a parallelogram (dissection to a rectangle)
The area of a triangle (dissection to a rectangle)
The area of a trapezoid (dissection to a rectangle)
Circles
The circumference and area of a circle
Angles
Angles as rotations versus angles as wedges
Making a rotation into a wedge angle
Exterior angles as turns while walking
Regular polygon and regular star polygons
Scaling and similarity
Dilating a triangle: scaling and similarity
Dilating a quadrilateral: scaling and similarity
Dilating a pentagon: scaling and similarity
Dilating a fish: scaling and similarity
Making base 10 blocks by scaling. Nonuniform scaling in 3 directions. Also allows nonuniform scaling of a rectangular prism.
Geometry in 3 dimensions
Makinga cone from a circle sector
Transformations and symmetry
Vectors and translations (Created in Java Sketchpad)
Checking a figure for reflection and rotation symmetry
Secondary mathematics
Geometry
(Most of the elementary geometry applets are valuable for secondary students, too. In U.S. schools, students get very few chances to explore geometry before being expected to do proofs in high school.)
Triangle inscribed in a circle
A geometric construction of square roots
Algebra
Solving quadratic equations with algebra tiles
Trigonometry
Radian measure: unrolling a circle
Trig functions as lengths
Sine wave controlled by sliders
Sine wave controlled by dragging
Logarithms
(These are all from Mathematical Intentions. There are more specialized applets there, as well as the connection between square roots and logarithms.)
An ancient Babylonian square root algorithm
An ancient Hindu square root algorithm
A medieval European square root algorithm
A slide rule for multiplying and dividing
A slide rule that also does roots, exponents, and logarithms
A circular slide rule
