Complex sentence: In 1998, The Learning Company was acquired by bought by Mattel in a notorious $3.6 billion deal which lead to Mattel quickly selling off their properties the following year to avoid bankruptcy.
Split into simpler sentences: In 1998, The Learning Company was acquired by bought by Mattel in a $3.6 billion deal. The deal turned out to be toxic and Mattel was forced to quickly sell off their properties the following year to avoid bankruptcy.