There are areas of knowledges and vital experience, about which can reason any of us. Except for a policy medicine and, certainly, economy behave to such spheres. And it is not casual, in fact economy — science is empiric, direct-coupled with practice. Everybody everyday runs into the economic phenomena and processes. All of us are active participants of everyday economic life, but far not all have a complete picture of what an economy is in actual fact.

As science an economy is an area of knowledges, studying an economic man, his actions and interests. It is called to determine how maximally effectively to use the limited resources — natural supplies, capitals, labour backlogs. Like all other fields of knowledges an economy includes the set of axioms and proofs, suitable for an analysis in any concrete terms. Economy however much science can be national, similarly however can be American physics or German mathematics. The costs of commodities are everywhere determined correlation of demand and supply. With growth of profit there are diminishing of his consumable part and growth — amassed.

But an economy has an of principle difference from exact and natural sciences: it deals not with a separate man on the uninhabited island, but with the member of society, subject to influence of traditions, national mentality, political institutes and predilections. Therefore the tool of economist has a national specific. Science is formed approximately similarly, as building foundation of which microeconomics serves as is built. The great economists of the pas created a theory — microeconomics, which studies relations between businessmen and hired workers, salespeople and buyers.

Leaving from axioms, economic science formulates laws: demand and supply, rareness, decreasing profitableness, maximum labour and capital productivity. Microeconomics is directly related to entrepreneurial activity, is as though a reference book, guidance for a businessman. At the same time the groups of enterprises and industry of the state also work in accordance with some rules, submit the action of certain economic laws which are studied by an economic theory.

In XVIII—XIX вв. a classic economic theory was created. It answered the necessities of development of industrial society, based on a peculiar and freedom of economic choice. Its founder is consider Adam Smit, value of studies of which like the invention of wheel; the "wheel" of national economy "revolves" the difficult systems of interdependent industries, forms a world economy. Meantime in public life and business practice there are problems which can not be settled only through traditional facilities. Economists begin to be interested in the questions of general order, combined demand, money circulation. It is impossible not to reminisce in this connection Leon Val'rase, creator of theory of general economic equilibrium.

XX ages were in history of economic idea the stage of macroeconomics. The large system — it the great number of small subsystems (firms and industries) not only, but already and new quality. Its actions are managed by other mechanisms. A macrosystem can not be described the categories of microeconomics (by a price, income, competition and other). New macroindexes, new methods and instruments, are here needed.

Usually attribute an economy to sciences humanitarian. It unright litigions. Today an economy does not simply exist without mathematics. In respect of macroeconomics, then it specially studies quantitative and spatial correlations by formulas, charts, geometrical figures. Mathematics enables to put in order the stream of information. Western economists mainly mathematically the ideas, for example hypothesis of Shumpetera, theorem of Kouza, effect to Pete, equalization of Fishera, paradox of Leont'eva etc.