Math

Business maths are mathematics used by commercial enterprises to record and manage business operations. Commercial organizations use mathematics in accounting, inventory management, marketing, sales forecasting, and financial analysis. ( Wikipedia )

Mathematics typically used in commerce includes elementary arithmetic, elementary algebra, statistics and probability. Business management can be made more effective in some cases by use of more advanced mathematics such as calculus, matrix algebra and linear programming. ( Wikipedia )

Interest calcualations
- Simple interest calculation Interest = Principal * Interest rate * Time ( I = P * R * T )
- w:Compound interest arises when interest is added to the principal, so that, from that moment on, the interest that has been added also earns interest. This addition of interest to the principal is called compounding.

w:Index (economics) - In w:economics and w:finance, an index is a statistical measure of changes in a representative group of individual data points. ( Wikipedia )
calculation of simple indices,
A w:price index (plural: “price indices” or “price indexes”) is a normalized w:average (typically a weighted average) of w:prices for a given class of goods or services in a given region, during a given interval of time. It is a w:statistic designed to help to compare how these prices, taken as a whole, differ between time periods or geographical locations. ( Wikipedia )
A w:consumer price index (w:CPI) measures changes in the price level of consumer goods and services purchased by households. ( Wikipedia )
A w:cost-of-living index is a theoretical w:price index that measures relative w:cost of living over time or regions. It is an index that measures differences in the price of goods and services, and allows for substitutions to other items as prices vary. ( Wikipedia )

w:Value added tax ( VAT )
The w:foreign exchange market (forex, FX, or currency market) is a form of exchange for the global decentralized trading of international currencies. ( Wikipedia )
The Current rate and the w:forward exchange rate (also referred to as forward rate or forward price) is the W:exchange rate at which a bank agrees to exchange one w:currency for another at a future date when it enters into a w:forward contract with an investor. w:Multinational corporations, banks, and other w:financial institutions enter into forward contracts to take advantage of the forward rate for hedging purposes. ( Wikipedia )

w:Compound interest calculation arises when interest is added to the w:principal, so that, from that moment on, the interest that has been added also earns w:interest. This addition of interest to the principal is called compounding. ( Wikipedia )

The time value of money is the value of money figuring in a given amount of interest earned or inflation accrued over a given amount of time. ( Wikipedia )