Q: Need help figuring out a formula in Pages

I am trying to figure out how to write a formula in a Pages table.

Basically, if the cell B3 has only the letter A or B, I want B7 to automatically fill with the word MATH, if the cell B3 contains the letter C or D, I want B7 to automatically fill with the word SCIENCE, and if B3 contains the letter E or F, I want B7 to fill with the word HISTORY. 

Is there a formula/function that will do this? Thank you!