I am a huge proponent of the open-source philosophy, especially where it pertains to education. CK12 has proven that a sensible, intelligently-organized text can be assembled under Creative Commons. Our district has adopted "Chemistry, 2nd Ed." as our primary text for all general chemistry sections. We printed a classroom set of 40 textbooks for less that $200. Students now carry USB flash drives, not 10 lb paper textbooks!

We love the materials on your website. This is a wonderful way for our teachers to experiment with using web-based resources in our classes. Thank you!

I love the concept, love how the organization is working, and love the website as a collaborative space for teaching professionals.

Thank you for providing this free service. As a low-tuition private school, resources such as ck-12 allow us to provide quality education without raising tuition.

Thank you for the materials and work created. It is refreshing to find up to date material easily accessed in so many platforms~ printed, tablet, computer, etc. I view CK-12 as a pioneer of the future of learning. Thank you and keep up the blessed work!

I think you are doing a great job and I was glad to incorporate your flexbooks into our eigth grade lesson plans using the Kindle for pc app... keep up the great work!

You all are a help to all students. You all are awesome!

Dear CK12 Support, I want to share with you that last year I used the CK12 Biology Text, Student Workbook and the Teacher Resources. I found these to be incredibly useful. They were my primary text and resource and they were comprehensive, well written and well organized. I especially appreciate that the workbook and resources were highly aligned with the student text. Taken all together, they provided a very adequate text for both my honors and standard sections of high school biology. As a result, I look forward to using other CK12 products. Many thanks and kindest regards.

I was and I am still amazed by the service, fantastic!

I tell everyone about CK-12! I really enjoy being able to bring all of our school books with us and not breaking my back to do it! Thanks again for developing FLEXBOOKS!!!!!

I'm very, very grateful to CK-12. CK12 is really a key resource for our learning!

I appreciate the work that your organization has done. It's wonderful to find a high quality curriculum. It's wonderful and astonishing that when that curriculum is free!

CK-12 has helped me learn and achive good grades.

You are a great resource!!! Thank you for getting the job done.

With the student that I am teaching science to, the material you have provided on your site is fantastic. You have made my job much easier by making this available. Thank you.

My students are enjoying the books! They are REALLY helpful! In a situation where funding doesn't permit the purchasing of mainstream texts, your texts have been a real godsend.

Thank you for making CK-12 a free source material. I use your resources extensively!

The FlexBooks are so much better than any other textbooks I have found. They allow my students to advance much further in their studies than they would in the public school setting.

You guys are revolutionizing public high school education. It's fantastic! Keep it up, please.

CK-12 Foundation is noble work for huminity and mankind

I think the improvements that are being made are wonderful. I believe that this system has much more to offer that some of the other currently popular student resources such as Khan Academy. I use KA as well but find the FlexBook package to be better.

I LOVE my CK-12 and I love what you have done with the concepts this year. For Algebra 2, we are supplementing with CK-12 this year and I love how I can find exactly what I need to give my daughter the specialized help she needs in specific areas. I also love how CK-12 now keeps track of what she has done and how long it takes, etc. In January, we will be using all of the English/Writing concepts and the tracking CK-12 does for me will be invaluable then. We found the Honors Biology program challenging, yet doable--even for a home school mom who had never taken an honors program in high school. Thank you for working hard to make Open Resource educational materials available to all.

You all are a help to all students. You all are awesome!

Thanks for all the help CK-12, it's a fantastic site.

CK-12 Foundation is noble work for huminity and mankind

I believe FlexBooks are the way of the future!

I love how I can use my chemistry FlexBook on my iPad and not carry around a heavy book!

Thank you for your wonderful study help...because of your site and my own school's help, I have become successful in earning a higher ACT score!!

CK-12 has created the most powerful digital text on the market and in the process is pioneering the digital text industry. The free Flexbooks allow for easy editting, ability to save in multiple file types, and student interactivity. After finding CK-12 Annandale Middle School decided against purchasing textbooks for our 8th grade science classes and used the savings and some grant funds to purchase iPads that the students use in class. Making the leap to a digital learning environment has provided the students at AMS with skills and experiences necesssary to be successful 21st Century learners.

I hadn't visited your site for a while and I am absolutely astounded and blown away by what you have put out there for the public. Wow, wow, wow! I am a homeschooling consultant who advises home-educators on how to school online from free resources and I will be including your incredible learning resource as a link on my website so that people can access your knowledge base. Thank you so much for this incredible service to humanity that you are providing, and congratulations to you all for the most beautiful, user friendly site. info/notes from class, and turn it into a more compressed "textbook."Although, this does take quite a lot of time it is extremely helpful for finals and the SAT's. Although my peers teased me for doing the extra work, your site inspired to continue making my study guides.

Love Love Love the "Traditional Textbook" feel. In other words, I have had to work with some "new" math textbooks that are absolutely worthless to the student on their own. These Flexbooks are written like the "textbooks of old" in that if the student is absent or needs further explanation when at home, away from school, they have a good shot on getting the information they need. Thank you for providing this resource to us.

Love Love Love what CK-12 has done so far. My students love it, too!

Like the Geometry textbook very much. We are a poor school district, but our students do have laptops. Because of you, we are able to provide a great text to the students.

High quality, simple, FREE! This enables me to move toward 'tailored learning' for each student.

First, I used your Biology textbook and (very) successfully completed the CLEP biology test!
I am now attempting to do the same for a Chemistry CLEP test. There are questions at the end of every lesson within each chapter. Is there any resource with the answers to those questions? They are very similar to the CLEP tests. Using questions from your text would be invaluable to help me study.
Thank you.

You guys are the best. You can change many lives, since you pretty much offer free education for many children around the US and the world.

Love your books and the click through features especially. It helps the content come alive for the student!

Thank you for the generosity of your efforts. My students have gained from your materials and I have been a better teacher. Thank you. I appreciate the higher order thinking required in most of your books and not just PRACTICE and MORE PRACTICE.

I really find your books extra ordinarily helpful in my studies. I have recommended this site for couple of my friends who were very impressed to see your Flex Books I had. I truly love this organization and have my thumbs up for you guys! Thank you tons.

We appreciate the tools provided by CK-12 to help in our children's home school education. CK-12 is a valuable resource for us. Thank you!

You guys are revolutionizing public high school education. It's fantastic! Keep it up, please.

I really appreciate your organization. I am 73 years old and it’s been over 55 years since I studied Chemistry. Four years ago when we were foster parents we adopted our last three charges. Now I have a 10,12 and 15 year old daughters. I’m disappointed with our schools here in Az so I’ve been homeschooling them for 2years now. This year chemistry is one of our subject so I’ve built up a lab and with help Home Science Tools and Robert Thompson (homechemlab.com) I am putting together A super Chem. course. I did this for my first child, now 48, I graduated from UCR and is an organic chemist for Babcock Labs in Riverside Ca. As I registered with your website I see you also have many other text books available. I download the Biology book. I am an electronics engineer and love teaching since the early 60s thanks to the USN. I pray that you will continue a wonderful service. Thanks again.

I really enjoy the site and it's very refreshing to have access to free exam prep material.

This is the first Science text book that my son has enjoyed. He is now getting it done and he is retaining it!

I love the idea behind the CK-12 learning resources. They are very stimulating and quite interactive; the pedagogy employed is very effective.

I *love* your flexbook system for Alg I and Geometry... This is a fantastic idea!

Awesome. Thank you. I work with kids with learning disabilities and the text seems to be very appropriate for them. Lots of examples, good reading level, to the point.

I love the work you guys are doing. I'm a physics teacher in Denver Colorado and I have been "following" the Peoples physics book for a couple of years and the work you guy have done to that book is incredible.

We are just beginning to explore CK-12. The possibilities are very exciting for us! Thanks for all you do for the betterment of our nation's young people. Your products and services will certainly help us advance the cause of education in this digital age we live in.

I like your organization because it is a great step to spread the education in the poor world. I really like CK-12 and hope it will continue to provide free resources to students like me.

I think that your site is awesome and I believe it is worth supporting at this time. I really believe that materials should be free for everyone! Thank-you!

Thank you everybody who is at ck12. For self learners like me this site is the greatest boon. May GOD bless you people!

CK-12 represents the future of education; knowledge should be available free to any that desire it.

Thank you! Without these tools it would be impossible for our family to educate our children in such a high standard due to the high price set on knowledge in printed form.

I really enjoy using ck-12, and I want to thank you for offering such a helpful website to students like me.

I love how I can use my chemistry FlexBook on my iPad and not carry around a heavy book!

I LOVE MY CHEMISTRY TEACHER FOR INTRODUCING CK-12 TO ME!!!!

CK-12 is a powerful learning tool because of its customization advantage.

I have a STEM girl (8th grade) who needs advanced content that is not faux/pseudo-science. It is difficult (and often expensive) to find quality secular science materials for home school use and we sincerely appreciate having access to these excellent materials for free via Kindle. Thanks!

Excellent site with amazing resources. The service you have provided is so greatly appreciated and I am grateful for the services you provide. Thank you for all you have done for children's education.

What you all have done, to open the door to educators to see how you all think, dream, and create. It is a wonderful process that all teachers would benefit from learning. Your programs have allowed me to invite the students to share and lead instead of expecting the teacher to deliver the information.

We appreciate the tools provided by CK-12 to help in our children's home school education. CK-12 is a valuable resource for us. Thank you!

Just discovered your site through a link on the creative commons website. I was very impressed with the design, content, and ease of use. I'll be using it for my kids during the summer to give them a jump start on next year.
Thanks!

Thank you so much for the materials provided online. With our transition to aligning our curriculum to national standards, we needed some supplemental materials to meet those standards. Your site and materials have helped me out tremendously! Thank you!

I appreciate the efforts of CK-12 to provide quality products for all educators, including homeschooling families. I appreciate that you allow homeschooling parents access to teacher material.

Thank you to everyone at CK12. You have been hugely important in my development as a teacher over the last several years. You are impacting the lives of many kids here in North Carolina.

Thank you, CK-12, for all that you do! Without your support, I could not have been as successful as I am now :)

I love the concept, love how the organization is working, and love the website as a collaborative space for teaching professionals.

I think the site is wonderful and we certainly appreciate the content being updated on a consistent basis.

Thank you for your wonderful study help...because of your site and my own school's help, I have become successful in earning a higher ACT score!!

I like your organization because it is a great step to spread the education in the poor world. I really like CK-12 and hope it will continue to provide free resources to students like me.

First of all, THANK YOU for assembling this extraordinary chemistry text. I am implementing it across the board for general chemistry at Kirksville High School (Missouri).

You guys are awesome and thank you so much for making this. I enjoy using it :)

This is an excellent resource that many of my students have found valuable!

I think the site is wonderful and we certainly appreciate the content being updated on a consistent basis.

As a Principal of a small private school, I wanted to express my thanks for the difference your flexbooks have made in our instructional content in the
STEM subject areas. As we complete our pilot program using your materials, both students and teachers express satisfaction with your materials.
Students seem to be impressed by the interactive nature of the texts and the multimedia content. Students have also commented on the ability to write in their textbooks, since we are able to provide personal copies of
their textbooks for $10 or less per subject. We also provide PDF formats of their textbooks on our intranet so they can review presentations made in
class at home for less than a dollar per text. While the textbook
publishers we used to purchase our STEM textbooks from continue to remind us that your flexbooks do not offer the eye-popping graphic content of their textbooks, we have found no significant drop in student interest or quality of instructional content. Also, our national test scores in areas
tested have shown no drop, and in many areas have gradually improved.

Our teachers seem most impressed with the ability to annotate or change content at will as curriculum needs, instructional focus or subject area knowledge changes.

I have to admit as a Language Arts/Social Studies teacher, I am a little jealous that such high quality open source materials are not available yet in my areas of expertise. I strongly encourage you and other open source
publishers to continue work to expand the "free or inexpensive knowledge" revolution in the field of education. As budgets continue to be so stretched, I sincerely appreciate your efforts.

I love the idea behind the CK-12 learning resources. They are very stimulating and quite interactive; the pedagogy employed is very effective.

My students are enjoying the books! They are REALLY helpful! In a situation where funding doesn't permit the purchasing of mainstream texts, your texts have been a real godsend.

I appreciate the efforts of CK-12 to provide quality products for all educators, including homeschooling families. I appreciate that you allow homeschooling parents access to teacher material.

Dear CK12 Support, I want to share with you that last year I used the CK12 Biology Text, Student Workbook and the Teacher Resources. I found these to be incredibly
useful. They were my primary text and resource and they were comprehensive,
well written and well organized. I especially appreciate that the workbook
and resources were highly aligned with the student text. Taken all
together, they provided a very adequate text for both my honors and
standard sections of high school biology. As a result, I look forward to
using other CK12 products.
Many thanks and kindest regards.

I am extremely grateful for the CK-12 materials it helps me home school my younger siblings. It gives me great ideas on how to order and plan their lessons.

CK-12 is an amazing program! I am so glad I found it!

We really love your products. The ability to access other material is really helpful for our teachers and students alike!

You guys are the best. You can change many lives, since you pretty much offer free education for many children around the US and the world.

Wonderful resource. works especially well for more kinetic children who are overwhelmed by a traditional textbook.

I am a rising sophomore at Cupertino High Schoool, and I have been using
your website for my studying, and review for quite a while now. It has
been extremely helpful, often times it explained things better than my
teacher. So thank you! It is a secret hobby of mine to type up
info/notes from class, and turn it into a more compressed "textbook."
Although, this does take quite a lot of time it is extremely helpful for
finals and the SAT's. Although my peers teased me for doing the extra work,
your site inspired to continue making my study guides.

Thank you for the materials and work created. It is refreshing to find up to date material easily accessed in so many platforms~ printed, tablet, computer, etc. I view CK-12 as a pioneer of the future of learning. Thank you and keep up the blessed work!

Great site with great resources. Well done one creating such an invaluable resource and making it free.

I randomly found your site when I was searching for some E-books,and
luckily found this. And I was amzed to see that you give such awsome books
for free! I am a math student and I love those books so so much, the details
are clear and perfect! These books will help me a lot!

Thanks for all the help CK-12, it's a fantastic site.

I enjoy using ck-12 because there are so many different ways to learn the same information, I feel that I can fully understand whatever concept I'm looking at much easier.

CK-12 is simply amazing!

I'm very, very grateful to CK-12. CK12 is really a key resource for our learning!

I enjoy using ck-12 because there are so many different ways to learn the same information, I feel that I can fully understand whatever concept I'm looking at much easier.