Decimals are the core fundamental of all financial markets. All decimals have dots, sometimes called periods, the dot or period indicates a place value that is less than the ones place. In the case of money, a decimal point indicates the cents. The decimal point separates numbers that are less than one from numbers that are smaller. Anything to the left of decimal is more than one and anything to the right of the decimal place is a value that is less than one.
Decimals are parts of a whole. For instance 0.74 is 74ths of a whole or 7 tenths and 4 hundredths of one. In the case of money that would be equal to 74 cents.