Frequently Asked Questions

Expii is a free, open, and interactive platform for crowdsourced explanations and practice problems in math and science.

We cover a wide range of topics, selected and organized by our curriculum director. Multiple crowdsourced explanations and practice problems at each topic show a diversity of perspectives and options.

Our editor helps people write interactive explanations and responsive questions, making it easy to create high quality digital content.

Anyone with an Expii account can write an explanation, practice problem, or solution. Our authors are teachers looking to provide an extra reference, students learning how to articulate their knowledge, and enthusiasts trying to challenge themselves and build a community resource.

Having different voices is what makes Expii strong and lets you find the explanation or question that helps you learn best. To make sure everything is correct, we have a team of content experts who moderate incoming content for accuracy and quality. In addition, you can upvote content that you think is awesome to help make sure that the best rises to the top.

Currently, we have maps for math (ranging from pre-algebra to theoretical math), astronomy, physics, chemistry, Earth science, and biology. While our content is primarily built for high school students, there are many topics that go into more advanced levels.

If you have a suggestion for the topic maps or a request for new content, contact support.

You don't need an account if you just want to read content, but having an account lets you write, edit, and upvote explanations. Accounts are free, and we do not share account information with third parties.

Fame is a measure of the impact you've had in building Expii. You get fame from writing explanations or problems, and you get even more fame when other people upvote those pieces.

Sign up by creating an Expii account with your email address. To get started, click on the "Join" button in the top right on www.expii.com. Follow the instructions to create an account and start exploring.

If you already have an Expii account, click the "Sign in" button on www.expii.comand enter your email and password. If you don't remember your password, just click "Forgot your password?" and we'll help you reset it.

No worries! If you forgot your password, click the "Sign In" button on www.expii.comand then click "Forgot your password?". Enter the email address associated with your Expii account, and we will send a link to let you set a new password.

You should get that email within a couple of minutes. If it's not showing up, try checking your spam folder in case the email filtered there. To avoid that, add Expii as a trusted contact or mark the email as "not spam" if you have that option.

Grandmaster is Expii’s latest learning innovation. We have created a learning algorithm that will adapt, measure, and rate user comprehension across topics in relation to problem difficulty. Our innovative algorithm and adaptivity is grounded in mathematical theory and adjusts with every user and every problem solved to give real time insight into the mastery of topics. This scoring system is transparent and based on Elo, where each problem and each learner has a rating that is refined as more users complete more problems.

To enter Grandmaster, use the topic mapto navigate to any subject and click the Practice! button. From there, Grandmaster will show you problems related to that topic based on your personal rating. You can practice general topics at high levels of the map, and specific topics by navigating further into the map

If you solve a problem correctly, you will see community solutions, your impact on the problem rating, and other fun stats.

If answered incorrectly, you will be given the option to try again, skip the problem, or reveal the answer.

In Grandmaster, every person and every problem starts with a base 1500 rating, which will change with each problem completed. To precisely gauge mastery of specific concepts, Grandmaster rates you on each individual topic level. The difficulty of problems provided adjusts to your mastery with each answer submitted. Since learning is limitless, there is no cap on how high your rating can reach.

The Grandmaster algorithm is currently in its alpha phase, which means that you can have even more significant impact on its creation. We need learners and teachers to help us build Grandmaster and refine its ratings. There are three ways that you can contribute:

• Solve problems

  When you solve problems you help set their difficulty rating, against which all future users will be compared.

• Submit your own problems

  When you submit the best of your own problems, you help define the level of quality problems we are looking to feature.

• Submit solutions

  For those who prefer to teach, your solutions will be what learners rely on to understand new concepts.

Our interactive map covers the majority of topics in high school math and science. Many of the topics are aligned with Common Core standards, while others go beyond them in breadth and depth. In addition, our editor makes it easy to create interactive, engaging explanations and practice problems.

Students can:

• practice written communication skills in math and science
• learn a topic by explaining it to others
• practice topics in an adaptive problem solving environment

Teachers can:

• add links to helpful explanations on homework sets
• create a flipped classroom by sharing instructional material on expii
• use Expii Solveto share fun math problems

Accounts are free and do not require real names.

To share teaching ideas or feedback, contact support.

Topic titles and intended content cover the majority of Common Core State Standards for Mathematics at the high school level. Science graphs are developed similarly with respect to Next Generation Science Standards.

You can use our standards resourceto find Expii topics for each standard.

If you know what you're looking for, you can use the search bar. If you want to explore a bit more, you can get to the topic map by clicking the map pin icon.

The topic map shows all of Expii's topics and how they fit together. Specific topics nest inside more general topics. Think of it like a textbook's table of contents: the whole book has a topic, and each chapter is a little more specific, and chapters might be divided into even more specific sections.

To get into the topic map, click on the map pin icon in the nav bar. If you are on a specific topic page already, the topic map will orient to show you where that topic is located.

Click inside a topic circle to zoom in and see its subtopics, or click anywhere outside the main topic circle to zoom back out a level. When you see a topic inside a rectangle (instead of a circle), that's the end of the line – it won't have any subtopics. You can click on those "final" topics to read explanations or add your own.

The colors in the topic map represent how well you know each topic. As your score increases, you'll see a new color start to wrap around the topic.

Topics with greyed out text could use some more contributions. Contribute to these topic to have the largest impact

When you're learning something new, sometimes the first explanation doesn't click and you need to hear it explained a different way. That's totally normal! We think it's great to see different perspectives and approaches to explaining a single topic.

Each topic is a collection of different explanations. Find the one that works for you, or add your own voice.

Upvotes are your way of communicating to the Expii community whether or not you thought an explanation, practice problem, or solution was awesome. If it was helpful, or funny, or well-written, give it an upvote!

Explanations, practice problems, and solutions are ordered by upvotes. You might find a low-ranked explanation that works great for you, but we want to make sure that the first thing you see for a topic is an explanation that a lot of people thought was good.

Sometimes, it's easier to learn when you see new things a little bit at a time rather than all at once. When reading an explanation, it might show you more after you answer a question correctly or say you're ready to continue.

Every time an explanation pauses for you to be ready, you'll have an option to expand the explanation. If you want to just go ahead and see the whole explanation at once, click the "Expand" button. Be careful of spoilers!

If you see an explanation or practice problem that's not quite right, click "Edit" to make changes. That will take you to the editor just like if you were writing a new explanation or problem, except you'll see everything that's already been written for the one you're editing.

You can edit explanations to fix errors or make the language more clear. If you think the topic should be explained in a totally different way, however, you should add a new explanation.

After you make the change, click "Submit suggestion." You'll be prompted to enter a short description for your edit. When you click "Submit," your edit will be sent to the original author as well as our moderators to wait for approval.

If you see an error while working on practice problems, click "Report" to let us know what's going on.

If you want to add your voice to Expii and write an explanation, start by using the search bar or topic map to find a topic to write about. You can add an explanation on any topic page. Here are some general guidelines:

1. Write an explanation, not just an answer

   Think about explaining the topic so that the reader understands it better, not just giving a formula or answer to copy down.

2. Think outside the box

   Do you have a creative way of thinking about the topic? We want you to share your approach, even if it looks different from what you might normally find in a textbook.

3. Ask questions

   Engage your readers by asking questions and prompting them to think about what they're learning – learn more here.

4. Show, don't (just) tell

   Images and videos that are relevant to your explanation can be a great way to get readers' attention.

To help keep this a friendly, educational space, please do not:

1. Use profanity

   Expii is for everyone, so please avoid mature or offensive language.

2. Copy without citing

   It's great if you want to share awesome explanations you've found, but make sure you've got the rights to post it and be sure to cite your source! Check out our terms and conditionsfor more information.

3. Write carelessly

   Students are looking to your explanations for help, so take the time to check for errors.

Just like explanations, you can add practice problems on any topic page. Here are some guidelines for writing effective problems:

1. Explain the problem scenario

   Use text, images, or diagrams to set up the problem.

2. Ask a question and mark the answer

   Your question can be multiple choice (with one or more correct answer options) or text entry. If you create a text entry question, be sure to specify how you expect answers to be formatted and try to anticipate all possible valid answers and formats.

3. Give feedback

   You can provide feedback for each answer option, but do not explain the solution as part of a practice problem. Solutions can be added separately after the problem is posted.

We don't buy into the idea that there's a "right" way to teach. We want your way, because that way is perfect for someone. But, if you're looking for some tips on how to write a great explanation, here are some best practice techniques:

1. Don't assume

   Great explanations are the ones that meet the students at their level. It can be hard to know what that level is, but remember that your reader is someone who needs help understanding the topic. Try to not assume too much preexisting knowledge – you can always include links to more advanced applications.

2. Use examples

   It can be hard to understand a new topic when everything is abstract. Make the topic concrete by showing an example or demonstrating an application.

3. Include visuals

   Media like images and videos can be great teaching tools because they allow learners to process information in more than one way. Visuals work best when they're relevant to the topic and paired with explanatory text.

4. Ask questions

   Questions help engage learners and let them check to see if they're following along. They're also a great way for you to provide interactive feedback. Is there a common misconception? Try providing that as an answer option and write feedback explaining why that isn't right.

5. Break it up

   Explanations that are endless blocks of text can be overwhelming and intimidating. Break it up with paragraph breaks and pause points to help your readers stay focused. If your explanation is particularly long, it becomes even more important to orient your readers.

6. Be yourself

   You might not be allowed to use personal pronouns in your English papers, but they're totally fine on expii! The best explanations are ones that are friendly and approachable – think about what your explanation would be if a friend asked you for help.

Adding questions to your explanations is a great way to check in with your reader. Use the toolbar to add a question block where you want it to appear in the explanation.

Your question can be multiple choice (with one or more correct answer options) or text entry. If you create a text entry question, be sure to specify how you expect answers to be formatted and try to anticipate all possible valid answers and formats.

Anything you add after a question block will be hidden to readers until they have answered or skipped the question. If you are writing a question for a practice problem (as opposed to inside an explanation), please read our guidelineson how to properly format problems.

To add an image, use the toolbar in the editor to add an image block where you want it to appear. You will have the option of dragging and dropping a file directly into the editor, or uploading a file from your computer.

To add videos, the editor will ask you to copy-paste the YouTube URL. Once uplodaded, you will have the option of truncating the video to a designated timeframe. You can also add annotations, which will appear underneath the video at marked times.

Plots and geometry diagrams can provide helpful visuals for your explanations, practice problems, and solutions. Use the toolbar to insert either a plot or a diagram where you want it to appear.

You can see examples of what you can make with plots here, and examples of geometry diagrams here.

You can use LaTeX to format math equations in text blocks or inside your questions. To have text processed as a math expression, surround it by dollar signs ($).