Common Sense Review
Updated December 2016

Math Open Reference

Visually plain, no-frills collection of math simulations
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Common Sense Rating 3
  • A simple home page groups subjects into easy-to-grasp categories.
  • Ads on the page might confuse users.
  • The Graphical Function Explorer facilitates quick understanding and visual connections.
  • Entry for cube sports an animation where users can "explode" the shape and manipulate it in all directions with the mouse.
  • Construction for "Copying a line segment" provides numbered instructions and animated diagrams that show how the protractor is moved and manipulated.
Interactive content wrapped in a simple package still delivers with tight, clear wording and digestible math chunks.
Ads can annoy and confusingly lead to other math sites.
Bottom Line
Free collection of math interactives and geometry construction tutorials.
Emily Pohlonski
Common Sense Reviewer
Classroom teacher
Common Sense Rating 3
Engagement Is the product stimulating, entertaining, and engrossing? Will kids want to return? 2

Missing real-world context or games to make math interesting. The site isn't visually appealing, but easy to navigate.

Pedagogy Is learning content seamlessly baked-in, and do kids build conceptual understanding? Is the product adaptable and empowering? Will skills transfer? 4

Concepts are well defined with clear language. The applets and "function explorers" provide visual representations of math concepts.

Support Does the product take into account learners of varying abilities, skill levels, and learning styles? Does it address both struggling and advanced students? 3

Content is offered in all of the languages offered through Google Translate, including Esperanto, Haitian Creole, and Basque. Additional opportunities to extend student knowledge are needed.

About our ratings and privacy evaluation.
How Can Teachers Use It?

Teachers can use Math Open Reference to easily project and step through constructions with the whole class. Next, students re-create them using the site until they are eventually able to do it with real drawing tools. Of course, when homework time rolls around, kids can peek back at the site if memory fails. Function explorers provide concrete illustrations of linear equations and more. Try letting students play with the sliders and see how changing different variables transforms the shape of the graph.

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What's It Like?

Math Open Reference is a free interactive math reference covering high school geometry, functions, and calculus. Five organizing topics cover plane, coordinate, and solid geometry, plus trigonometry and calculus. A few function explorers and a general online scientific calculator arm kids with tools that help them visualize what all these numbers and formulas actually mean.

Most entries open with a definition, follow with concise explanations of relevant concepts, and then end with links to other relevant topics. Embedded "Try This" activities invite kids to interact with dynamic diagrams by moving intersecting points, lines, or vertices and watching the results. A large number of entries are actually constructions -- step-by-step animations showing kids exactly how to find the "center of a circle using any right-handed object," for example.

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Is It Good For Learning?

Math Open Reference has some hidden gems despite its plain package and often confusing sidebar ads for other math sites. Concise, accurate explanations provide a solid foundation for a series of dynamic construction and manipulation applets that pull kids into the experience and build deeper, concrete understanding of geometry concepts. The constructions in particular show kids through animated protractors and pencils (and downloadable worksheets) how to bisect an angle, divide a line segment into equal parts, or draw a parallel line through a point.

While site owner John Page calls it a textbook in his mission statement, the terms reference and construction guide are more precise. Other sites featuring math simulations such as Desmos provide formative assessments that teachers can monitor; exercises with immediate feedback and a teacher dashboard are missing from Math Open Reference. Also missing is standards alignment, though many of the simulations align to the Common Core Math Standards.   

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See how teachers are using Math Open Reference

Lesson Plans