Simplify the following text for a Grade 3 native English-speaking person.
Original: Ð Ð Ì Ð '' Ð Ð Ñ Ð Ð Ì Ð Ð Ð Ñ Ð `` Ð 3\/4 Ñ Ð Ð Ñ Ñ ` Ð ; Pronunciation : mih-kha-ILL ser-GHE-ye-vich gor-bah-CHOFF ) ( born March 2 , 1931 ) , was the leader of the Soviet Union from 1985 until 1991 .
Simplified: Ð Ì Ð Ð '' Ð 3\/4 Ð Ð 1\/2 Ð Ð ' Ð Ñ Ð Ð Ì Ð 1\/2 Ñ Ð Ð Ñ ) , in 1957 .