CK-12 Algebra Explorations is a hands-on series of activities that guides students from Pre-K to Grade 7 through algebraic concepts.

This site from Richland Community College provides lecture notes to a class on Algebra. It covers a wide array of topics including functions, quadratic equations, inequalities, and much more.

This MAP Classroom Challenge provides students with an engaging and thought-provoking activity about notebooks, pens and cash registers to learn about solving equations in two variables. Includes assessment materials, student handouts, online resources, and student work samples. The entire unit can be downloaded in PDF format.

Children will learn the term variable and then work to "attack" a problem using what they know about the relationship between multiplication and division to solve for an unknown.

Students use substitution to find the values of equations and expressions they wrote using appropriate math symbols.

This video segment from Cyberchase introduces the idea of inverse operations as Bianca imagines herself as a spy.

Using a Project Planning Guide, students work through the stages of creating an app from scratch. This is the first day of a three-day project. This lesson is devoted to the planning phase.
This lesson is aligned to CSTA standards.

Students translate the plans they documented in Part 1 of the Practice PT to a working program in App Lab through a series of steps.
This lesson is aligned to CSTA standards.

The final lesson in the Practice PT progression is devoted to feedback and improvements to the Decision Maker App. Students work with classmates to review and update the functionality of their apps before submitting the final project.
This lesson is aligned to CSTA standards.

To begin the lesson students explore sample apps similar to the ones they'll be able to build by the end of the unit. Then students complete an unplugged activity with plastic baggies and sticky notes to build a mental model of how variables are used to move and store information. The lesson ends with a synthesizing discussion and students adding key vocabulary to their journal.
This lesson is aligned to CSTA standards.

In this lesson students work with partners to investigate several versions of the "Thermostat App" to understand how variables store and update information. To begin, students examine a version of the app where the temperature displayed changes each time a button is clicked. The next two versions of the app demonstrate how variables can store strings. Students learn about the patterns they are observing, specifically "Counter Pattern with Event" and "Variables with String Concatenation Pattern". To conclude the lesson, students review and discuss the programming patterns that they will make use of in the programs they write.
This lesson is aligned to CSTA standards.

In this lesson students spend most of their time practicing using the skills and processes they have learned about variables. At the conclusion of the lesson students discuss the main things they realized and still have questions about at the conclusion of this lesson.
This lesson is aligned to CSTA standards.

Using Programming Patterns and a step-by-step approach students make their own version of a Photo Liker app. At the beginning of the lesson students are able to explore a working version of the app. They are then given the design elements of the app but begin with a blank screen. A progression of levels guides students on the high level steps they should use to develop their app but leaves it to them to decide how to write the code. At the end students submit their apps which can be assessed using a provided rubric.
This lesson is aligned to CSTA standards.

Site provides some different examples of categorical data and discusses the use of two-way tables.

Students are challenged to design a way to drop a raw egg from varying heights without letting the egg break. Creative thinking and evaluation of results are critical to the project.

The CyberSquad uses algebra to figure out how many gleamers they need and how many power glows are produced by each gleamer as they must power up a Cyberspace ship in this video from Cyberchase. [1:43]

Learn how to identify the dependent and the independent variables in a word problem. [2:09]

Khan Academy learning modules include a Community space where users can ask questions and seek help from community members. Educators should consult with their Technology administrators to determine the use of Khan Academy learning modules in their classroom. Please review materials from external sites before sharing with students.

Model with algebra tiles to generate equivalent expressions. This video focuses on visualizing the distributive property.

Students practice multiple-choice problems with factors and divisibility.

Khan Academy learning modules include a Community space where users can ask questions and seek help from community members. Educators should consult with their Technology administrators to determine the use of Khan Academy learning modules in their classroom. Please review materials from external sites before sharing with students.

In Module 4, students extend what they already know about unit rates and proportional relationships to linear equations and their graphs.  Students understand the connections between proportional relationships, lines, and linear equations in this module.  Students learn to apply the skills they acquired in Grades 6 and 7, with respect to symbolic notation and properties of equality to transcribe and solve equations in one variable and then in two variables.

Find the rest of the EngageNY Mathematics resources at https://archive.org/details/engageny-mathematics.