This short video and interactive assessment activity is designed to teach second graders about using real maps (english lengths and distances).

This short video and interactive assessment activity is designed to teach second graders an overview of elapsed time.

This short video and interactive assessment activity is designed to teach third graders an overview of telling time to 1-minute intervals.

This short video and interactive assessment activity is designed to give fourth graders an overview of elapsed time.

This short video and interactive assessment activity is designed to teach fourth graders about elapsed time in a sequence of events - word problems.

This short video and interactive assessment activity is designed to teach third graders about determining unknown angles in parallelograms.

This short video and interactive assessment activity is designed to teach third graders about determining unknown angles in trapezoids.

This short video and interactive assessment activity is designed to teach third graders about determining unknown angles within rectangles and squares.

This short video and interactive assessment activity is designed to give fourth graders an overview of capacity - word problems.

This short video and interactive assessment activity is designed to teach fourth graders about determining the order of decimals in word problems.

This short video and interactive assessment activity is designed to teach third graders about determining the unknown angle in an isosceles triangle.

In this deterministic cellular automata model, interactions between neighboring automata are described using a prisoner's dilemma. Limiting dispersal of seeds of annual plants can permit heterogeneous co-existence, whereas thorough mixing instead allows one subpopulation to dominate quickly.

A web page and interactive applet show how to compute the length of the diagonals of a rectangle. A rectangle is shown that can be resized by dragging its vertices. As you drag, the diagonals are continuously recalculated. Text on the page explains calculation. For those who prefer it, in a formula that is given. Applet can be enlarged to full screen size for use with a classroom projector. This resource is a component of the Math Open Reference interactive geometry reference book project at http://www.mathopenref.com.

A web page and interactive applet show how to compute the length of the diagonals of a square. A square is shown that can be resized by dragging its vertices. As you drag, the diagonals are continuously recalculated. Text on the page explains calculation. For those who prefer it, in a formula that is given. Applet can be enlarged to full screen size for use with a classroom projector. This resource is a component of the Math Open Reference interactive geometry reference book project at http://www.mathopenref.com.

An interactive applet and associated web page that demonstrate the diameter of a circle. The applet shows a circle and a diameter line, the ends of which can be dragged to show that the diameter passes through the center and has a constant length regardless of where on the circle it is drawn. The web page has the circle-related formulae. Applet can be enlarged to full screen size for use with a classroom projector. This resource is a component of the Math Open Reference Interactive Geometry textbook project at http://www.mathopenref.com.

This task supports students in correctly writing numbers. Because students have to trace the number, instead of coloring in a bubble with the number in it or circling the correct number, they gain handwriting practice as well as counting and addition practice.

This short video and interactive assessment activity is designed to teach second graders about determining time changes in 5-minute intervals.

This short video and interactive assessment activity is designed to teach third graders about solving for beginning time in 5-minute intervals - word problems.

This short video and interactive assessment activity is designed to teach fourth graders about ending time in 5-minute intervals - word problems.

This short video and interactive assessment activity is designed to teach second graders an overview of subtraction (numbers to 1,000).