Visualize the electrostatic force that two charges exert on each other. Observe how changing the sign and magnitude of the charges and the distance between them affects the electrostatic force.

Students practice counting sequences by standing in a circle and counting one by one.

Students who work on this task will benefit in seeing that given a quantity, there is often more than one way to represent it, which is a precursor to understanding the concept of equivalent expressions.

This task gives students another way to practice counting and gain fluency with connecting a written number with the act of counting. This task should be introduced by the teacher and would then be a good independent center.

The most engaging way to practice counting with students is to have them count meaningful things in their lives. Since five-year-olds are very focused on themselves this is easily done by allowing them to count themselves, their friends and objects within the classroom that relate to their daily lives.

This challenging problem and brainteaser gives first graders an opportunity to compose and decompose squares.

This is an instructional task related to deepening place-value concepts. The important piece of knowledge upon which students need to draw is that 10 tens is 1 hundred.

The objective of this lesson is to gain automaticity counting to 100 and to establish the importance of multiples of ten. The final goal of this lesson is for students to be able to count by tens and articulate the term for this.

This task involves solving equations with rational coefficients, and requires students to use the distributive law ("combine like terms"). The equation also provides opportunities for students to observe structure in the equation to find a quicker solution, as in the second solution presented.

This task presents a real world application of finite geometric series. The context can lead into several interesting follow-up questions and projects. Many drugs only become effective after the amount in the body builds up to a certain level. This can be modeled very well with geometric series.

You are preparing your family’s emergency kits in case there is a need to leave your home quickly, or stay in your home without electricity or water. You need to be able to create an emergency supply kit that includes a lightweight water filtration device that is low cost. This will provide you with clean water regardless of your water source.

In this project, you will gain knowledge of natural disaster preparedness through the Red Cross Pillowcase project. You will research and experiment with the water cycle to learn how water is naturally filtered. You will then design and build a water filtration device that could filter water in an emergency situation.

Students practice crossing from one family to the next in counting forward with this concentration game.

This word problem requires students to create expressions to calculate gas milage for a vehicle.

One common mistake students make when dividing fractions using visuals is the confusion between remainder and the fractional part of a mixed number answer.

This module includes information to help find, evaluate, adapt and share open educational resources to meet learning outcomes and objectives. The module also offers information on how to describe and organize OER to enable its discovery by future users.

With your mouse, drag data points and their error bars, and watch the best-fit polynomial curve update instantly. You choose the type of fit: linear, quadratic, cubic, or quartic. The reduced chi-square statistic shows you when the fit is good. Or you can try to find the best fit by manually adjusting fit parameters.

With your mouse, drag data points and their error bars, and watch the best-fit polynomial curve update instantly. You choose the type of fit: linear, quadratic, cubic, or quartic. The reduced chi-square statistic shows you when the fit is good. Or you can try to find the best fit by manually adjusting fit parameters.