When a company makes plans for how much to produce and what prices to set, it needs information. The company needs to predict the level of supply that will be required to meet demand. It needs to set prices that will keep the business running. In the same way, governments need this information for the whole economy. The total level of demand for all products and services is called the aggregate demand. The total supply is called the aggregate supply.

The demand for products and services is how much is wanted. For a company, the demand comes from customers. For a whole economy, things are a little more complicated. Demand in the whole economy comes from the following:

- from consumers, because they buy products and services (consumption)

- from companies, because they invest money to build factories and buy machines (investment)

- from the government, because they spend money on services and projects (government spending)

- from exports, because these are sales to customers in other countries (export)

Although aggregate demand is made up of many things, it behaves in the same way as demand for a single product. For example, demand rises when incomes rise. The same applies to aggregate demand. Similarly, demand falls as prices rise. The same is true for aggregate demand. You can see this relationship shown in figure 1 on page 63. The vertical axis shows prices. The horizontal axis shows real national income. Real national income is the value of all the services and products produced by the whole economy. It's calculated in the same way as aggregate demand (consumption, investment, government spending and exports). You can sec from the curve that national income (and therefore aggregate demand) increases as prices fall.

Changes in any of the four things which make up aggregate demand will cause a shift in demand. For example, if the government decides to spend a huge amount of money on building new hospitals and schools, this will have an effect on the whole economy. Aggregate demand will increase at all price levels. This is shown in aggregate demand curve 2 (AD2) in figure 1.

The supply curve for an individual product or service is very simple. As the company increases its supply to the market, it increases the price. But what about aggregate supply for the whole economy? This is more complex. In the short run, aggregate supply follows the same trend as the supply for a single product. Supply rises as prices rise. However, the long run is different. In the long run, supply is not affected by price. In the long run, production is limited by the factors of production. In other words, what a country can supply depends on the number of factories it has, the number of people working and the availability of raw materials. This is why the long run supply curve in figure 2 on page 63 is a straight line.

Переведите на английский язык:

1. Разрушительным крахом для американской экономики стала Великая депрессия, воздействие которой ощущалось практически во всех странах мира. Депрессия изменила отношение к экономической науке.

2. После депрессии 1930-х годов главными целями любого правительства, во избежание серьёзных спадов в экономике, стали устойчивый экономический рост и контроль над инфляцией.

3. Налогово-бюджетная политика связана с налоговой системой и бюджетом страны. Посредством этой политики правительство может воздействовать на располагаемый доход, спрос и экономический рост.

4. Главным инструментом кредитно-денежной политики являются процентные ставки.

5. Совокупный спрос — это спрос в экономике в целом. Он включает спрос со стороны потребителей, компаний, правительства и потребителей за рубежом.

6. Стоимость всех услуг и товаров, произведённых экономикой в целом, образует реальный национальный продукт.

7. Тенденция роста или снижения предложения и совокупного предложения в краткосрочном периоде одинакова, но в долгосрочном периоде рост совокупного предложения зависит не от цены, а от имеющихся в экономике факторов производства.