If you're refereeing to fractions then it is the solidus bar that separates the numerators from the denominators.
between numbers
Math is really just another language in which you communicate using numbers and fraction bars, and decimals etc.. But what math is, i woudln't say there is any concrete way of answering that.
The range
How much is between two numbers.
There are no differences in the numbers.
The range of a group of numbers is the difference between the highest and lowest numbers
the interval between numbers in a sequence
The distance between two or more numbers
Real numbers are numbers that exist from negative infinity to positive infinity and everything in between. real numbers consist of every number you are used to. Imaginary numbers are numbers that aren't used in conventional math (such as i)
20 101 a three digit number and i don't know what is the answer
It is an ordered set of numbers such that the difference between adjacent numbers is a constant.
Rational numbers are numbers that can be written as a fraction. Irrational numbers cannot be expressed as a fraction.