Complex sentence: Of Armenian descent, Khachiyan was born in St. Petersburg and moved to Moscow with his parents at age 9 where he later earned a Ph.D. in computational mathematics in 1978 and a D.Sc.
Split into simpler sentences: Of Armenian descent, Khachiyan was born in St. Petersburg and moved to Moscow with his parents at age 9. There he later earned a Ph.D. in computational mathematics in 1978 and a D.Sc.