Questions & Answers about Las matemáticas son difíciles para mí.
Why is it son (are) when the English translation says "Mathematics is"?
Why is it difíciles instead of difícil?
Adjectives in Spanish have to match the noun they describe in both number (singular or plural) and gender. Because las matemáticas is plural, the adjective describing it must also be plural: difíciles.
Why do we use son (from ser) instead of están (from estar) here?
Why does mí have an accent mark in para mí?
The accent mark is used to tell two identical-sounding words apart. Mí (with the accent) means "me" and is used after prepositions like para. Mi (without the accent) means "my", as in mi libro (my book).