CK-12 FlexBook 2.0 vs Illustrative Mathematics

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.

Illustrative Mathematics provides IM Math, a problem-based core mathematics curriculum for transitional kindergarten through grade 12. The IM Math v.360 sequence runs from transitional kindergarten through Algebra 2. Lessons ask students to solve meaningful problems, explain their reasoning, compare strategies, and connect mathematical ideas across lessons, units, courses, and grades. Built-in resources include discussion routines, support for English learners and students with disabilities, unit assessments, session checkpoints, and lesson cool-downs. AccessIM provides the complete curriculum online for free, with implementation resources and downloadable, printable PDFs for teachers and students, without a time limit. The curriculum aligns with the Common Core State Standards for Mathematics. Schools can obtain print materials and enhanced digital platforms through IM Certified partners such as Imagine Learning, Kendall Hunt, and Kiddom. Partner platforms may add rostering, assignments, reporting, and progress monitoring.