難しい: difficult

not ... at all

even if ...,...cannot

very, exceedingly, awfully / (before a negative form) not at all, at all, by no means

mathematics (field of study)

question, problem on homework etc. / a question; a matter (of time etc.) / a problem (something that needs to be dealt with); a trouble / an issue; a matter

(mathematics) pure mathematics

applied mathematics

mathematician

Alternative spelling of 組合せ数学 (“combinatorics”)