New York-based McGraw Hill Education is buying a 20 percent stake in Area9 Aps, an adaptive-learning company.

Area9, headquartered in Copenhagen, develops adaptive-learning technology that aims to deliver personalized training and education. The technology alters the presentation of the material for individuals.Terms of the deal weren’t disclosed.

The two groups have worked together since 2007 to develop products, such as McGraw-Hill LearnSmart, a study tool, and LearnSmart Advantage, a suite of adaptive learning products.

Private equity firm Apollo Global Management LLC (NYSE: APO) agreed to acquire the McGraw Hill Companies’ (NYSE: MHP) education unit for $2.5 billion in November. 

For more on education M&A, see "With Dealmakers, School is Still in Session."