Complex sentence: Uranus's mass is roughly 14.5 times that of the Earth, making it the least massive of the giant planets, while its density of 1.27 g/cm³ makes it the second least dense planet, after Saturn.
Split into simpler sentences: Uranus's mass is roughly 14.5 times that of the Earth, making it the least massive of the giant planets. A density of 1.27 g/cm³ makes Uranus the second least dense planet, after Saturn.