The focus of this task is on understanding that fractions, in an explicit context, are fractions of a specific whole. In this problem there are three different wholes: the medium pizza, the large pizza, and the two pizzas taken together.

Many students will not know that when comparing two quantities, the percent decrease between the larger and smaller value is not equal to the percent increase between the smaller and larger value. Students would benefit from exploring this phenomenon with a problem that uses smaller values before working on this one.

The purpose of this task is for students to compare a number and its product with other numbers that are greater than and less than one.

In this task students are required to compare numbers that are identified by word names and not just digits. The order of the numbers described in words are intentionally placed in a different order than their base-ten counterparts so that students need to think carefully about the value of the numbers.

In this task students are required to compare numbers that are identified by word names and not just digits. The order of the numbers described in words are intentionally placed in a different order than their base-ten counterparts so that students need to think carefully about the value of the numbers.

In this video from Cyberchase, Harry must score a total of 50 points in various events to qualify for the Northern Hemisphere games in New Orleans.

Explore a NetLogo model of populations of rabbits, grass, and weeds. First, adjust the model to start with a different rabbit population size. Then adjust model variables, such as how fast the plants or weeds grow, to get more grass than weeds. Change the amount of energy the grass or weeds provide to the rabbits and the food preference. Use line graphs to monitor the effects of changes you make to the model, and determine which settings affect the proportion of grass to weeds when rabbits eat both.

An interactive applet and associated web page that demonstrate the concept of complementary angles (angles that add to 90 degrees). The applet shows two angles. You can drag the endpoints of each angle and the other angle changes so that they always add to 90 degrees. They are drawn in such a way that it is visually obvious that together they form a right angle, although they are separate on the page. The angle measure readouts can be turned off for class discussions. 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.

In the everyday electrical devices we use calculators, remote controls and cell phones a voltage source such as a battery is required to close the circuit and operate the device. In this hands-on activity, students use batteries, wires, small light bulbs and light bulb holders to learn the difference between an open circuit and a closed circuit, and understand that electric current only occurs in a closed circuit.

This problem is intended to reinforce the geometric interpretation of distance between complex numbers and midpoints as modulus of the difference and average respectively.

Students will use the decomposition of a compost pile to visualize fractions as parts of a whole.

In a multi-week experiment, students monitor the core temperatures of two compost piles, one control and one tended, to see how air and water affect microbial activity. They daily aerate and wet the "treated" pile and collect 4-6 weeks' worth of daily temperature readings. Once the experiment is concluded, students plot and analyze their data to compare the behavior of the two piles. They find that the treated pile becomes hotter, an indication that more microbes are active and releasing heat. Through this activity, students see that microbes play a role in composting and how composting can be used as a carbon management process.

Students explore the concept of biodegradability by building and observing model landfills to test the decomposition of samples of everyday garbage items. They collect and record experiment observations over five days, seeing for themselves what happens to trash when it is thrown "away" in a landfill environment. This shows them the difference between biodegradable and non-biodegradable and serves to introduce them to the idea of composting. Students also learn about the role of engineering in solid waste management.

This task is preliminary to F-LE Compounding Interest with a 5% Interest Rate which further develops the relationship between e and compound interest.

This task develops reasoning behind the general formula for balances under continuously compounded interest. While this task itself specifically addresses the standard (F-BF), building functions from a context, a auxiliary purpose is to introduce and motivate the number e, which plays a significant role in the (F-LE) domain of tasks.

This task asks students to perform computations involving complex numbers using the given information.

Accuracy of measurement in navigation depends very much on the situation. If a sailor's target is an island 200 km wide, sailing off center by 10 or 20 km is not a major problem. But, if the island were only 1 km wide, it would be missed if off just the smallest bit. Many of the measurements made while navigating involve angles, and a small error in the angle can translate to a much larger error in position when traveling long distances.

The purpose of this series of tasks is to build in a natural way from accessible, concrete problems involving volume to a more abstract understanding of volume. The purpose of this first task is to see the relationship between the side-lengths of a cube and its volume.

The purpose of this series of tasks is to build in a natural way from accessible, concrete problems involving volume to a more abstract understanding of volume. In this iteration, we do away with the lines that delineate individual unit cubes (which makes it more abstract) and generalize from cubes to rectangular prisms.

The purpose of this series of tasks is to build in a natural way from accessible, concrete problems involving volume to a more abstract understanding of volume. Here, we are given the volume and are asked to find the height.