Complex sentence: President Obama, accompanied by Mrs. Obama, will deliver the Summit's keynote address on April 10, and former Presidents Carter, Clinton, and George W. Bush will offer addresses on April 8, April 9, and April 10, respectively.
Split into simpler sentences: President Obama, accompanied by Mrs. Obama, delivered the Summit's keynote address on April 10. Former Presidents Carter, Clinton, and George W. Bush also participated in the Summit, offering speeches on April 8, April 9, and April 10, respectively.