Simplify the following text for a Grade 12 native English-speaking person.
Original: Helmut Heinrich Waldemar Schmidt ( 23 December 1918 in Hamburg ) is a German politician and was Chancellor of the Federal Republic of Germany from 1974 to 1982 .
Simplified: Helmut Heinrich Waldemar Schmidt ( ; born 23 December 1918 ) is a German Social Democratic politician who served as Chancellor of West Germany from 1974 to 1982 .