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

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

Students practice data collection by gathering data within the classroom on common causes of allergies. They examine and interpret data charts on national trends in allergies.

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 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 about determining time changes in 5-minute intervals.

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

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

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

The CyberSquad tracks Digital position in time and then studies graphs to figure out what Hacker is scheming in this video from Cyberchase.

This task helps students understand the relationship between digit placement and the value of a number.

This task gives students the opportunity to verify that a dilation takes a line that does not pass through the center to a line parallel to the original line, and to verify that a dilation of a line segment (whether it passes through the center or not) is longer or shorter by the scale factor.

This task requires students to think of dimes and pennies as fractions of dollars.

This task does not actually require that the student solve the system but that they recognize the pairs of linear equations in two variables that would be used to solve the system. This is an important step in the process of solving systems.

The purpose of this task is to illustrate through an absurd example the fact that in real life quantities are reported to a certain level of accuracy, and it does not make sense to treat them as having greater accuracy.

This purpose of this task is to help students see two different ways to look at percentages both as a decrease and an increase of an original amount. In addition, students have to turn a verbal description of several operations into mathematical symbols.

Students discover the mathematical constant phi, the golden ratio, through hands-on activities. They measure dimensions of "natural objects"—a star, a nautilus shell and human hand bones—and calculate ratios of the measured values, which are close to phi. Then students learn a basic definition of a mathematical sequence, specifically the Fibonacci sequence. By taking ratios of successive terms of the sequence, they find numbers close to phi. They solve a squares puzzle that creates an approximate Fibonacci spiral. Finally, the instructor demonstrates the rule of the Fibonacci sequence via a LEGO® MINDSTORMS® NXT robot equipped with a pen. The robot (already created as part of the companion activity, The Fibonacci Sequence & Robots) draws a Fibonacci spiral that is similar to the nautilus shape.

This task asks students to find a linear function that models something in the real world. After finding the equation of the linear relationship between the depth of the water and the distance across the channel, students have to verbalize the meaning of the slope and intercept of the line in the context of this situation.

Using circumference, this segment measures the total distant traveled by two carousel riders after the carousel has rotated 10 times.