Americans display income with a dollar symbol followed by the numerical value that includes thousands separators and a decimal point. For example, a person would write an income of five thousand, two hundred dollars and three cents as "$5,200.03."
Some international currencies have slightly different rules. For example, some countries use a period as a thousands separator and a comma as the decimal separator. In these countries, a person would write the income as "$5.200,03."
Sometimes people write large incomes in shorthand, using "K" as a symbol for thousands. In this case, a person rounds the income to the nearest thousand, so instead of writing "$5,200.03," a person might write "$5K" or even "$5.2K."