This short video and interactive assessment activity is designed to teach second graders an overview of subtraction (numbers to 100) - word problems.

This marbel counting iteration of greater than, less than, and equal to with a specific "target number" help strengthen the concept for students.

This series of activities and lesson notes is part of a unit in which the purpose is, “Students will interpret visual information in order to make informed consumer decisions.” The activities begin with informal exploration.

These Guidelines for Improving Math Materials for English Learners (the Guidelines) were developed to provide specific guidance to developers of mathematics content on key areas of English language development that must be embedded across a curricula, in units, and in lessons so that English learner students (ELs) can access and engage in grade-level content.

In this video segment from Cyberchase, the CyberSquad determines the fairness of a game in which there are three shapes distributed equally on nine squares.

This problem could be used as an introductory lesson to introduce group comparisons and to engage students in a question they may find amusing and interesting. More generally, the idea of the lesson could be used as a template for a project where students develop a questionnaire, sample students at their school and report on their findings.

This task involves fraction multiplication that can be solved with pictures or number lines.

In this activity students measure their hand span. A line graph is used to record the data from the glass.

In this group task students collect data and investigate whether there is a relationship between height and hand size among the students in the class.

Students explore the concept of similar right triangles and how they apply to trigonometric ratios. Use this lesson as a refresher of what trig ratios are and how they work. In addition to trigonometry, students explore a clinometer app on an Android® or iOS® device and how it can be used to test the mathematics underpinning trigonometry. This prepares student for the associated activity, during which groups each put a clinometer through its paces to better understand trigonometry.

This article provides links to standards-based science and literacy lessons about weather, climate, polar climates, and climate change.

This article highlights hands-on or multimedia lesson plans about plant structures, growth and development, seed production, and dispersal. Science lessons are paired with suggested literacy lesson plans. All lessons are aligned to national standards.

Harry keeps track of the number of times he sneezes in certain locations to try to diagnose the cause of his allergy in this video segment from Cyberchase.

Harry and his students look at various arrangements of classroom desks in this video from Cyberchase.

This is a challenging task, suitable for extended work, and reaching into a deep understanding of units. The task requires students to exhibit MP1, Make sense of problems and persevere in solving them. An algebraic solution is possible but complicated; a numerical solution is both simpler and more sophisticated, requiring skilled use of units and quantitative reasoning. Thus the task aligns with either A-CED.1 or N-Q.1, depending on the approach.

Spreadsheets Across the Curriculum module. Students calculate the number of days it takes for participants in a hypothetical weight-reduction program to reach a target weight. QL: rates of change.

This is an activity about utilizing proportional mathematics to determine the height of lunar features. Learners will use the length of shadows to calculate the height of some of the lunar features. This activity is Astronomy Activity 6 in a larger resource entitled Space Update.

A web page and interactive applet illustrating the properties of a hexagon (6 sided polygon). The applet shows a hexagon where the user can drag any vertex to reshape it. User can see that the interior and exterior angles are constant in a regular hexagon, but vary in an irregular version. Controls allow the display or hiding of the diagonals, and triangles within the hexagon. The web page lists the properties of a hexagon including interior angles, exterior angles, sum of exterior angles, area, number of diagonals and number of internal triangles. Links to pages with generalized properties of all polygons. 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.

The goal of this task is to use geometry study the structure of beehives. Beehives have a tremendous simplicity as they are constructed entirely of small, equally sized walls. In order to as useful as possible for the hive, the goal should be to create the largest possible volume using the least amount of materials. In other words, the ratio of the volume of each cell to its surface area needs to be maximized. This then reduces to maximizing the ratio of the surface area of the cell shape to its perimeter.

This Module describes the components of high-quality mathematics instruction: a standards-based curriculum and evidence-based practices. It also highlights a number of evidence-based practices as well as other classroom practices that teachers can use to teach mathematics (est. completion time: 1.5 hours).