数学(shù xué) - maths in Mandarin

数学 (shùxué) is maths, mathematics as a school subject. 数 (shù) means "number" and 学 (xué) means "study, learning" (the same 学 in 学校 xuéxiào, school, and 学生 xuésheng, student), so the compound is literally "the study of numbers".

Note the tone: as the noun "number, mathematics" it is shù, fourth tone; the same character read shǔ, third tone, is the verb "to count", as in 数一数 (shǔ yi shǔ), "count them up". Mixing these up is a very common tone slip.

数学 (shùxué) pairs naturally with other subject words like 科目 (kēmù), subject, and with exam and result vocabulary, since it is one of the subjects British and Chinese learners alike tend to describe as either their best or their worst, rarely anything in between.