Today, Short form is most commonly used in most English speaking countries. The change in the United Kingdom to Short form numbering happened in 1974. Because of this, in Short form a billion is one thousand millions (10 9) while in Long form it is one million millions (10 12). Short form numbering is based on thousands and Long form is based on millions. This is mainly because of American finance. The American way or 'Short form' for naming large numbers is different from the European way or 'Long form' of naming large numbers. With the same number, it would be said to be 642 billion, 500 million (US) or 642 milliard, 500 million (Eur).

When naming by grouping, each group is the name of the group. Still counting the number of numbers after the first number (in this case, after the 6 there are 11 numbers) you need to include the ones that are not zero in the formula, but after a decimal point. When large numbers have many different decimals in them, such as 642 500 000 000, naming them with scientific notation is about the same, but with one difference. If the number is named by grouping, it is five hundred quintillion ( American) or 500 trillion ( European). For example, the number 500,000,000,000,000,000,000 can be called 5 x 10 20 in scientific notation since there are 20 zeros behind the 5. There are two main ways of naming a number: scientific notation and naming by grouping. Naming very large numbers is relatively easy.

List of prime numbers to 100 000