Idiom Testing

Translate this sentence into English with the appropriate English idioms taking into account how both languages use idioms to indicate something is  difficult and explain your choices:  Čeština je jazyk težký jako olovo pro nečechy, ale lehký jako pírko pro Čechy. 

Translate this sentence into Czech: I never took calculus in high school.

Translate this sentence into Czech: I never took calculus in high school. Provide detailed commentary about your choices and explain why you rejected some options.