This video from Khan Academy gives a good explanation of perimeter and how it is calculated.

The Khan Academy video gives a good introduction to the concept of area. The video from Math Playground explores area and perimeter.

This is a graphic that students might find helpful for remembering how to find circumference of a circle.

This video from Khan Academy demonstrates how to find circumference.

This activity is designed for older students. It may be challenging for fifth and sixth graders.

This lesson would be a good way to introduce circumference to students. It would be especially good for visual learners.

This graphic shows the formula for calculating the area of a circle.

The video shown by clicking on the link gives a demonstration on how to find the area of a circle.

The lesson shown in the link is intended for grades 6-8 but could possibly be adapted for younger students.

This blog lists some good resources and lesson plan ideas for teaching volume.

This video would be a good resource for introducing volume to students in grades 2 and 3.

This video shows a step by step demonstration of how to calculate the volume of a cylinder. The lesson plan shown in the link allows students to explore volume of a cylinder and other 3D objects.

This is a fun video that would be a good resource for teaching volume of pyramids and cones. The link contains several lesson plans and resources for teaching volume.

This video from Khan Academy shows how to calculate the volume of a sphere. Click on the link for lesson plans on finding the volume of a sphere.

Students should have the opportunity to explore and become proficient in using non-standard units, the Customary System, and the Metric System.Explore the NCTM website for lesson plans and other teaching ideas.

This site has many resources that you can use to teach measurement.

This video demonstrates how to convert temperatures in Celsius to Fahrenheit

This site has resources and activities that can be used for teaching volume and capacity.

The video discusses distance and length in Customary units and would be appropriate for older students. The link to the Education.com site lists a variety of measurement activities for several grade levels.

This is a good overview of the Customary System of measurement. This would be good to use with students in first through third grade.

These are some ideas for teaching the metric system.

This graphic lists the metric units used for weight and mass.

This graphic shows an easy way for students to remember equivalent measurements.

This video shows how to convert temperature in Fahrenheit to Celsius.

This site has resources, lesson plans, and activities for teaching the metric system in the elementary classroom.

This site provides a good overview of the metric system for younger students.

This video gives some good ideas for teaching measurement with non-standard units. Younger students, as well as older students would enjoy this activity.

Khan Academy--introduction to the Pythagorean Theorem

Infographic on the Pythagorean Theorem

The site in the link lists a number of lesson plans to teach the Pythagorean Theorem for 6th through 9th graders. These lessons could be modified for younger students.

The lesson plan in the link contains a great interactive activity that can be used to teach both surface area and volume.

The activity in the link is a good one for visual learners.

The lesson plan in the link is a fun Harry Potter themed lesson suitable for 6th grade. It could be modified for younger or older students.

This video gives a step by step look at finding surface area of 3D shapes. The lesson plan in the link is suitable for grades 6-8.

The lesson plan in the link provides connections between geometry and the real world which would be interesting to students.