In mathematics, z represents all integers, whether positive or negative, such as -2,-1, 0, 1 and so on.
Mathematically, q represents all rational numbers, that is, fractions of finite integers and fractional parts (3/8), etc. , including fractions with infinite cycles of fractional parts, for example, 2/3, etc. Infinitely cyclic decimal numbers are called irrational numbers. All irrational numbers and rational numbers add up to the real number set R.
Little knowledge:
Real numbers correspond to imaginary numbers, which can be identified by imaginary numbers I, such as 1+i, 2i/3, etc.