Complex sentence: In the mid 1950s Howard Hughes purchased through the 1990s Hughes Tool Company Nevada Operations and the Summa Corporation acquired additional holdings of undeveloped land along the western edge of the Las Vegas Valley.
Split into simpler sentences: In the mid 1950s Howard Hughes purchased through the 1990s Hughes Tool Company Nevada Operations. The Summa Corporation acquired additional holdings of undeveloped land along the western edge of the Las Vegas Valley.