This tasks examines how to calculate the area of an equilateral triangle using high school geometry.

This short video and interactive assessment activity is designed to teach second graders about finding the capacity of water with illustrations (metric units).

This short video and interactive assessment activity is designed to teach fourth graders about finding the capacity of water with illustrations (metric units).

This short video and interactive assessment activity is designed to teach third graders about finding the expression not matching a given number.

This short video and interactive assessment activity is designed to teach fourth graders about finding the expression not matching a given number.

This short video and interactive assessment activity is designed to teach fourth graders about finding the incorrect equations.

This short video and interactive assessment activity is designed to teach fourth graders about finding the number from figure patterns.

This short video and interactive assessment activity is designed to teach fourth graders about finding the total time given a distance between two objects.

An interactive applet and associated web page that provide step-by-step instructions on how to find the center of a circle using any right-angled object, such as a piece of paper. The method uses Thales Theorem to draw two diameters, which intersect at the circle center. The animation can be run either continuously like a video, or single stepped to allow classroom discussion and thought between steps. 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 provide step-by-step instructions on how to find the center of a circle using only a compass and straightedge. The method used involves constructing the perpendicular bisectors of two random chords. The bisectors intersect at the center of the circle. The animation can be run either continuously like a video, or single stepped to allow classroom discussion and thought between steps. 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 provide step-by-step instructions on how to find the foci of a given ellipse using a compass. The animation can be run either continuously like a video, or single stepped to allow classroom discussion and thought between steps. 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 helps students solidify their understanding of linear functions and push them to be more fluent in their reasoning about slope and y-intercepts. This task has also produced a reasonable starting place for discussing point-slope form of a linear equation.

This task "Uses facts about supplementary, complementary, vertical, and adjacent angles in a multi-step problem to write and solve simple equations for an unknown angle in a figure (7.G.5)" except that it requires students to know, in addition, something about parallel lines, which students will not see until 8th grade.

This task asks students to solve addition and subtraction equations with different structures so that they are able to see the connections between addition and subtraction more easily.

This short video and interactive assessment activity is designed to teach fourth graders about determining rate.

In this task students are asked to write an equation to solve a real-world problem. There are two natural approaches to this task. In the first approach, students have to notice that even though there is one variable, namely the number of firefighters, it is used in two different places. In the other approach, students can find the total cost per firefighter and then write the equation.

This task is the first in a series of three tasks that use inequalities in the same context at increasing complexity in 6th grade, 7th grade and in HS algebra. Students write and solve inequalities, and represent the solutions graphically.

This task is the second in a series of three tasks that use inequalities in the same context at increasing complexity in 6th grade, 7th grade and in HS algebra. Students write and solve inequalities, and represent the solutions graphically.

This task is the last in a series of three tasks that use inequalities in the same context at increasing complexity in 6th grade, 7th grade and in HS algebra. Students write and solve inequalities, and represent the solutions graphically. The progression of the content standards is 6.EE.8 to 7.EE.4 to A-REI.12.