The concept of 65.438+0.5 billion is that a family has no worries about eating and drinking for generations. Internationally, people with net worth between 65.438+million yuan and 65.438+0 billion yuan are usually called rich people. Modern mathematics is generally decimal, and 1 billion is equal to10 billion, and 1500 million is equal to1500 billion. Decimal system is a number system based on 10. There are two kinds of decimals: decimals with no concept of value, and Haros decimals and Boulami decimals in ancient Greece, ancient Egypt and ancient India all belong to this category. In fact, this is a universal decimal system, that is, all decimal one, all decimal two, and so on.