Standard 8.NS.1 requires students to "convert a decimal expansion which repeats eventually into a rational number." Despite this choice of wording, the numbers in this task are rational numbers regardless of choice of representation. For example, 0.333 and 1/3 are two different ways of representing the same number.

This short video and interactive assessment activity is designed to teach second graders about converting dollars into cents.

This short video and interactive assessment activity is designed to teach fourth graders about converting feet to compound units.

This task gives students word problems with a given a set of a specified size and a specified number of subsets. The questions ask the student to find out the size of each of the subsets.

This short video and interactive assessment activity is designed to give fourth graders an overview of conversion between cups, pints, quarts and gallons.

This short video and interactive assessment activity is designed to teach fourth graders about converting gallons and quarts into cups.

This short video and interactive assessment activity is designed to give fourth graders an overview of conversion of metric units of weight.

This short video and interactive assessment activity is designed to teach fourth graders about converting inches to compound units.

This task provides an opportunity to work on the Standard for Mathematical Practice 3 Construct Viable Arguments and Critique the Reasoning of Others.

This short video and interactive assessment activity is designed to teach fourth graders about converting years into weeks.

This short video and interactive assessment activity is designed to teach fourth graders about converting years to days.

This short video and interactive assessment activity is designed to give fourth graders an overview of comparison of weights (english units).

An interactive applet and associated web page that demonstrate the concept of a convex polygon - one where all interior angle are less than 180 degrees. The applet shows an irregular convex polygon initially. The user can drag any vertex, change the number of sides in the range 3..99, and make it regular or irregular. When the polygon is convex, the polygon is so flagged. It is shown that regular polygons are always convex. The goal is to show through experimentation what the concept of convexity really means. 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.

While the task as written does not explicitly use the term "unit rate," most of the work students will do amounts to finding unit rates. A recipe context works especially well since there are so many different pair-wise ratios to consider.

These games support student development of the concept of ordered pairs as they play to win each game.

This is a set of three, one-page problems about how astronomers use coordinate systems. Learners will plot a constellation on a coordinate plane and/or plot the route of Mars Science Lab (MSL aka Curiosity) on the surface of Mars. Options are presented so that students may learn about the MSL mission through a NASA press release or about the coordinate plane by viewing a NASA eClips video [7 min.]. This activity is part of the Space Math multi-media modules that integrate NASA press releases, NASA archival video, and mathematics problems targeted at specific math standards commonly encountered in middle school.

An interactive applet and associated web page that describe the concept of the coordinate plane (Cartesian Plane). The applet shows the plane, its axes, origin and related controls. The user can drag a point around and see the coordinates change, and click anywhere to create new points. The origin can be dragged to emphasize or eliminate certain quadrants. The grid, axis pointers and coordinates can be turned on and off. The coordinate display can be turned off to permit class exercises and then turned back on the verify the answers. The applet can be printed as it appears on the screen to make handouts. The web page has a narrative description of the concept. 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.

A brief refresher on the Cartesian plane includes how points are written in (x, y) format and oriented to the axes, and which directions are positive and negative. Then students learn about what it means for a relation to be a function and how to determine domain and range of a set of data points.

An interactive applet and associated web page that describe the concept of a point in coordinate geometry. The applet show one point initially, but clicking anywhere adds more. As the points are dragged, the coordinates are seen to change. The grid, axis pointers and coordinates can be turned on and off. The coordinate display can be turned off to permit class exercises and then turned back on the verify the answers. The applet can be printed as it appears on the screen to make handouts. The web page has a narrative description of the concept, including the definitions of abscissa, ordinate, coordinates, ordered pair. The 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.

An interactive applet and associated web page that demonstrate the concept of coplanar objects - those that lie in the same plane. The applet presents two planes. In one plane there are two rectangles that can be dragged around and which lie in the same plane always. The other is a rectangle that can be dragged but always lies in a plane orthogonal to the first. 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.