#### Beacon

**New editor released!**

We've heard many requests to make it even easier to create rich content. It's always been our goal to create a system which empowers everyone with a vision of an interactive lesson to turn it into reality - without needing to know how to program. :)

Our first version, eML, helped to reduce the barrier significantly, but today, we've released an even easier-to-use lesson editor! It's still under intense development, and so you'll see it grow through leaps and bounds over the next few days. Give it a spin, and share your feedback! We'd be happy to improve it to the liking of our community. :)

**Girls on expii!**

Attention all females of the expii community! Po-Shen Loh and I started a Facebook page for all the girls on expii so that we can boost the number of girls on this site (and hopefully in the world of mathematics in general) and inspire other young girls to be interested in math as well! If you're interested in joining, please find us on Facebook and we'll add you to the page!

#### Mission: Algebra

**Distributive Property**

@Benjamin We have the distributive property here: https://www.expii.com/map/9124 (if you search "distributive property" this is the first result).

It's possible that it's missing somewhere else though---were you looking for it somewhere else? Let us know.

#### Mission: Astronomy

**Astronomy Edit-a-Thon, 2015 October 22 16:00 Pacific / 19:00 Eastern Time**

Hi Michael! When is the next astronomy edit-a-thon? :)

#### Mission: Biology

#### Mission: Calculus

**Specific useful substitutions article**

@Moor-Xu There's also a https://www.expii.com/topic/5440 (Summary: How to Compute Integrals) topic now.

#### Mission: Chemistry

#### Mission: Earth Science

#### Mission: E&M

#### Mission: Geometry

**Constructible Numbers?**

Hi everyone!

I'm new to expii, and I've only just started to explore all the content here. I noticed that there isn't yet a topic on constructible numbers; will that be coming in the future? I think I have some writing that could contribute to that topic.

**Weekly Global Jam Sat Feb 21: Constructions (11am Eastern / 9:30pm India / 5pm Central Europe)**

OK, I've posted an explanation here:

https://www.expii.com/the-basic-constructions/

Feedback is welcome!

#### Mission: Mechanics

**Expii Jam on Wed Feb 25 at 9pm Eastern: Waves**

Hi! Since @Po-Shen-Loh is currently on a plane to Munich en route to the Romanian Masters in Mathematics (wish team USA luck!), I'll be running this Jam today. Here's just some links to the pages about Waves that people can post in.

https://www.expii.com/frequency-and-period/

https://www.expii.com/peaks-troughs-wavelength/

https://www.expii.com/transverse-vs-longitudinal/

https://www.expii.com/phase/

https://www.expii.com/wave-velocity/

https://www.expii.com/interference/

Since all these links have at most 1 post and no exercises, any contribution is very very helpful! Feel free to ask any questions, discuss any ideas, write/edit articles, etc. I'll be writing about interference in the meantime.

**Expii Jam Wed Jan 28 at 9pm Eastern: Energy**

Thanks @Harrison-Grodin for coming today! You can continue, but I think that I'm done writing for the day. Thanks for a good Jam! I'll keep this page open in case you have questions or comments.

#### Mission: Thermodynamics

#### Be rational

**USA TSTST 2015 solutions**

Hi!

Does anyone have the solutions for the USA TSTST 2015, especially problems 3 and 6, since there are no correct solutions posted on AoPS as of now?

#### How do I...

**How do I delete a post?**

@Po-Shen-Loh Can I get https://www.expii.com/t/existence-of-the-dodecahedron-1193?type=explanation&id=5144 deleted too, please? I accidentally typed this when I meant to type it in another tab, and saved it.

#### Feature requests

**Profile Pictures for Expii.com main site accounts?**

Hi Qinzhuo,

We pull profile images from gravatar. So if you add an image to the email you use for Expii, we'll pull it down.

Best,

Andrew

**Next Topic Button seems to be gone?**

I remember a long time ago, there used to be a next topic button at the bottom of each page. I thought it seemed to be particularly useful. Can anyone tell me what happened to it?

#### Bug reports

**A few bug-reports about some Expii Solve problems**

Re: 19.4, I am fairly sure that the answer is not 271 or 272. I got the answer it accepts and it's definitely correct, and I checked with wolfram|alpha.

The rest I agree at least somewhat with. I have my own bug report:

5.3: "The Stock Market": Okay, this is an okay problem with only minor potential ambiguities. I solved it, so I thought, but it said I was wrong. So I checked my work several times over and still got the same answer. Maybe I was interpreting the question wrong, I thought, so I tried some similar answers out but none of them worked. It says "round to the nearest whole percent", so I tried 0.xy, .xy, xy%, and also tried adding more digits, but nothing worked. Finally I just wanted to know what answer it accepted so I tried every single whole percentage from 0% to 100%; it accepted none of them. I did this again just to make sure I hadn't missed anything. Now I am still fairly confident that I had the correct answer to begin with, and it looks like the problem just doesn't accept it. I'd be happy to write a solution for it too, if I ever get the green box! What's so puzzling is that apparently 214 people have solved this question which does not appear to have an answer.

This is the last #3 question that I have not solved, and so would like to just be done with it at this point.

**Can't edit solution to Expii Solve problem**

@Jacob-Zhang Thanks for reporting this! We're on it right now! :) @Daniel-Liu also messaged me about this. We really appreciate having such a responsive community!

#### Resources

**Practice Resources**

@Andrew-Yang

The books are fine if you get the PDF version of it and print it yourself.

**Applied Mathematics Book**

same place

You mean Caltech?

By the way, someone suggested that all books should have this warning

#### News

**The Improving Mathematics Education in Schools (TIMES) Project**

http://www.amsi.org.au/index.php/school-education-mainmenu/times-project

http://www.amsi.org.au/index.php/school-education-mainmenu/times-modules

Check these out! So many hidden gems in this world (the internet in particular). :) We'll definitely be consulting this for the upcoming Algebra map (which might include number theory and some counting as well)!