CK-12 FlexBook 2.0 vs TESSA OER

CK-12 FlexBook 2.0 provides customizable digital textbooks for K–12 subjects including science, math, and social studies. Lessons can combine text with PLIX interactives, simulations, adaptive practice, and related learning materials. Adaptive Practice draws questions from a library of more than 150,000 and adjusts selections based on student answers. Teachers can assign lessons, videos, interactives, and practice to whole classes or differentiated groups, then view progress reports. Educators can reorder chapters and edit or add content in customized FlexBooks. The service works in browsers on laptops, desktops, Chromebooks, tablets, and mobile devices, and is listed at free. Standalone Simulations and PLIX Interactives require a tablet-size screen or larger. Users may download PDFs of FlexBooks they create or customize, though interactive content may not render; CK-12-created PDFs are not downloadable. CK-12 says it is still converting all core content to FlexBook 2.0. Listed SSO or LMS partners include Google Classroom, Canvas, Schoology, Kiddom, Clever, and ClassLink.

TESSA OER is a free education research and development project founded in 2005 that works with partners to support primary and secondary teachers across sub-Saharan Africa. Its open educational resources are linked to national curricula and offered in multiple language and country versions. The collection contains 90 subject-based modules: 75 structured primary units and 15 secondary units. Modules provide practical activities, case examples, classroom materials, and guidance on teaching strategies for engaging learners. Handbooks and toolkits support teachers and teacher educators, while the materials cover professional learning from initial teacher education through continuing development. A shared space lets teachers and teacher educators exchange adaptations. Published under an open Creative Commons licence, the resources are free to use, adapt, and share. Materials are available online and offline in digital and printed formats. Teachers may use them independently or integrate them into pre-service and in-service training programmes.