Approximate number system

An approximate number system is a way of thinking about how numbers are related to one another without being exact. It is like a rough estimate. For example, if you had three apples and someone asked you how many apples you had you could say "about three". This means you have between two and four apples, but not exactly three. Another example is if you wanted to know how much money you had in your wallet. Instead of counting out your coins you might say "about five dollars". This means you have between four and six dollars, but not exactly five.