flexbooks.ck12.org

Main Information

ℹ️

Title: K-12 FlexBooks | CK-12 Foundation

Description: CK-12’s free, standards-aligned, digital textbooks are customizable, integrated, and interactive, allowing users to create 200,000+ localized FlexBooks.

Keywords: empty

Page Encoding: utf-8

Page Filesize: 296 KB

Server Information

🖥️

IP: 3.164.68.58

Location: United States,US,37.751,-97.822,America/Chicago

Http Server: apache/2.4.58 (ubuntu)

Encoding: utf-8

Meta Tags List

🏷️

equiv: origin-trial content: A7vZI3v+Gz7JfuRolKNM4Aff6zaGuT7X0mf3wtoZTnKv6497cVMnhy03KDqX7kBz/q/iidW7srW31oQbBt4VhgoAAACUeyJvcmlnaW4iOiJodHRwczovL3d3dy5nb29nbGUuY29tOjQ0MyIsImZlYXR1cmUiOiJEaXNhYmxlVGhpcmRQYXJ0eVN0b3JhZ2VQYXJ0aXRpb25pbmczIiwiZXhwaXJ5IjoxNzU3OTgwODAwLCJpc1N1YmRvbWFpbiI6dHJ1ZSwiaXNUaGlyZFBhcnR5Ijp0cnVlfQ==
property: og:site_name itemprop: name name: author content: CK-12 Foundation
property: fb:app_id content: 159884644067996
itemprop: url content: https://www.ck12.org
itemprop: telephone content: (650) 494-1302
charset: utf-8
name: viewport content: width=device-width, initial-scale=1, minimum-scale=1.0
name: google-site-verification content: wHx0f-Udlfd7ZNYNrIXpJVpjjO8nSH5RE0jIX8V-jIM
name: google-translate-customization content:
name: application-name content: CK-12 Foundation
name: msapplication-TileColor content: #003300
name: msapplication-TileImage content: //static.ck12.org/assets/favicon/web-app-manifest-192x192.png
property: og:description name: description content: CK-12’s free, standards-aligned, digital textbooks are customizable, integrated, and interactive, allowing users to create 200,000+ localized FlexBooks. helmet: true
property: og:url content: https://flexbooks.ck12.org/flexbooks/student/
itemprop: provider content: CK-12 Foundation
itemprop: name
itemprop: description
itemprop: url content: https://flexbooks.ck12.org/flexbooks/student/

Internal Links

🔗

External Links

🌐

Whois Information

📄

domain_name: ck12.org

update_date: 2026-05-06T01:03:50.485Z

update_time: 1778029430

creation_date: 2006-12-16T08:37:03.681Z

creation_time: 1166258223

expiration_date: 2028-12-16T08:37:03.681Z

Whois Raw Data

📋

            Domain Name: CK12.ORG
Registrar: Amazon Registrar, Inc.
Domain Status: client transfer prohibited
Registry Expiry Date: 2028-12-16T08:37:03.681Z
Creation Date: 2006-12-16T08:37:03.681Z
Updated Date: 2026-05-06T01:03:50.485Z
Name Server: NS-1136.AWSDNS-14.ORG
Name Server: NS-161.AWSDNS-20.COM
Name Server: NS-1687.AWSDNS-18.CO.UK
Name Server: NS-977.AWSDNS-58.NET
REGISTRAR Contact: Amazon Registrar, Inc.
>>> Last update of RDAP database: 2026-07-06T21:40:10Z

SEO Audit

🔍

Technical SEO

✓

Response Code

200

Status 200 OK - page loads correctly.

✓

Character Encoding

Page: utf-8, Header: utf-8

Character encoding consistent between HTML and headers.

✓

Page Size

303246 bytes

Page size acceptable for fast loading.

!

Resources

109 total

Too many resources. Optimize and combine files for better performance.

✓

Hreflang Tags

0 hreflang tags

Add hreflang tags if you have multilingual content.

!

Robots.txt

Missing

Add robots.txt file to control search engine crawling.

!

Sitemap

Not found

Add sitemap.xml and reference it in robots.txt.

✓

HTTPS

Yes

Secure HTTPS connection enabled.

✓

Compression

gzip

Gzip or Zstd compression enabled for faster loading.

!

Caching

Not set

Add cache-control headers to improve loading speed for returning visitors.

✓

Page Speed

2.64 ms

Excellent loading speed.

On-Page SEO

✓

Title

K-12 FlexBooks | CK-12 Foundation

Good title length (30-60 characters).

✓

Meta Description

CK-12’s free, standards-aligned, digital textbooks are customizable, integrated, and interactive, allowing users to create 200,000+ localized FlexBooks. Lenght:152

Good meta description length (100-160 characters).

!

H1 Heading

2 found - "Interact with Your Math & Science Textbooks in a Whole New Way"

Use only one H1 heading per page. Remove extra H1 tags.

!

Word Count

202

Content very short. Aim for at least 500 words for better SEO.

!

Canonical Tag

Add canonical tag to prevent duplicate content issues.

✓

Duplicate Meta

[]

No duplicate meta tags found.

✓

Keywords

empty

Meta keywords set (note: not used by major search engines).

Content and UX

✓

Language

en

Language attribute properly set.

!

Images

67 total, 51 missing ALT

Add ALT text to images for accessibility and SEO.

✓

Viewport

width=device-width, initial-scale=1, minimum-scale=1.0

Viewport meta tag properly set for mobile devices.

!

Open Graph

Missing: og:title, og:image

Add missing OpenGraph tags for social media sharing: og:title, og:image

✓

Structured Data

1 JSON-LD scripts

Structured data (JSON-LD) found.

Search Phrases - Google

🔍

Position	Phrase	Page	Snippet
2	write the rule	/cbook/ck-12-concept...	Writing Function Rules A functionrule expresses the output value in terms of all operations performed on the input value . A function rule can be expressed either using words or ...
2	water and life	/cbook/ck-12-biology...	Water and Life Water, like carbon, has a special role in living things . It is needed by all known forms of life. Water is a simple molecule, containing just three atoms.
2	write the times in words	/cbook/ck-12-first-g...	Time Conversion between Words and Numbers In this lesson we will learn how to convert time between numbers and words . The most common way to express time in words is just to say the time in the form ...
2	write time in words	/cbook/ck-12-first-g...	Time Conversion between Words and Numbers The most common way to express time in words is just to say the time in the form HOUR MINUTES . lesson content. [Figure 2]. We learned in the last lesson that ...
3	k e q	/cbook/ck-12-chemist...	Equilibrium Constant (Keq) The equilibrium constant (Keq ) is the ratio of the mathematical product of the concentrations of the products of a reaction to the mathematical product of the ...
3	plant cycle	/cbook/ck-12-cbse-sc...	Life Cycle of a Plant Life Cycle of a Plant is defined as the journey of a plant from a seed to a mature plant and back to producing seeds again. Stages: Seed → Germination → ...
3	animal plants	/cbook/cbse-science-...	Wildlife: Animal and Plants - Definition, Types, Examples ... Flora and fauna are terms used to describe plant and animal life in a particular area. They are essential components of wildlife.
3	time in words	/cbook/ck-12-first-g...	Time Conversion between Words and Numbers Express the time in a digital format, as hour and minute with a colon . Write Times in Numbers. What time is it now? We are going to learn how to write down ...
3	work example	/cbook/cbse-physics-...	Work - Defintion, Types, Formula and Examples 6 июн. 2023 г. — The kids who are playing football in the picture above are using force to move their bodies and the football, so they are doing work . The kids ...
5	2 5 50 6 18	/cbook/ck-12-concept...	Number Patterns Let's look at an example of a pattern that uses multiplication. Name the next value in the series. 2 , 6 , 18 , 54, _____ ... 5 , 10, 6 , 12, 8, 15, 11, _____

Additional Services

💎