Mathematics (from Greek μάθημα máthēma, "knowledge, study, learning") is the study of such topics as quantity, structure, space, and change. It has no generally accepted definition.
Mathematics is a versatile art; it can be applied to widely different purposes. Math has no morality; it does not care what it counts or what it proves.
Brian Stableford, Ashes and Tombstones, in Peter Crowther (ed.) Moon Shots (1999), reprinted in David G. Hartwell (ed.) Year's Best SF 5 (2000), p. 412
Poor air quality is a major health risk, causing lung diseases, cardiovascular diseases, and cancer. Air pollution also impacts the environment, affecting the quality of fresh water, soil, and ecosystems.
EN 
CS
DE
ES
FR
HU
IT
PL
PT
РУ
SK
TR
УК
AR
中文
