This task can be used to either build or assess initial understandings related to rational approximations of irrational numbers.

The CyberSquad proves that the area of Hacker's land is equal to the area of Judge Trudy's land in this video segment from Cyberchase.

Students must calculate the volume of a cone in this real world task.

This task provides the opportunity for students to reason about graphs, slopes, and rates without having a scale on the axes or an equation to represent the graphs. Students who prefer to work with specific numbers can write in scales on the axes to help them get started.

The purpose of this task is to help develop students' understanding of addition of fractions; it is intended as an instructional task.

The purpose of the task is for students to compare signed numbers in a real-world context.

In this model eliciting activity (MEA), students are hired by a travel magazine to determine if two airlines that fly into Chicago are equally reliable. They examine data of flight arrival delay times for both airlines flying out of the same city. They first identify measures that can be used to compare the two airlines. Working in small groups, the students decide the size of a meaningful difference between the airlines for each measure and use that information to determine a rule that for deciding if one airline is more reliable than another. The students apply their rule to flight arrival delay data for the two airlines from four additional departure cities, and use the results to write a report to the magazine editor on whether or not one airline is more reliable than the other. This activity can serve as an introduction to ideas of central tendency and variability, and prepares students for formal approaches to comparing groups.

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.

This short video and interactive assessment activity is designed to teach third graders about comparing numbers using greater than and less than.

This short video and interactive assessment activity is designed to teach fourth graders about comparing values of two numbers.

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.

This short video and interactive assessment activity is designed to teach second graders about comparing and writing decimal inequalities in word problems.

This short video and interactive assessment activity is designed to teach third graders about comparing the values of numbers to 1,000 - word problems.

This assignment exposes students to data on economic growth and development as commonly measured by per capita GDP and the Human Development Index (HDI) for 100 countries of the world. There is a big debate about how good an indicator HDI is compared to GDP per capita as a measure of development.

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.

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.

This short video and interactive assessment activity is designed to teach third graders about finding and completing the number patterns.