YOU SAID:

I am very good at math on opposite day

INTO JAPANESE

私は反対の日に非常に数学が得意

BACK INTO ENGLISH

I on the contrary very good at math

INTO JAPANESE

私は逆に非常に数学が得意

BACK INTO ENGLISH

On the contrary I so good at math

INTO JAPANESE

逆に私は数学が得意

BACK INTO ENGLISH

Conversely I was good at math

INTO JAPANESE

逆に私は数学が得意だった

BACK INTO ENGLISH

Conversely I was good at math