Use a number line to identify if you need to round up or round down. The whole numbers are equally spaced on this number line. The values increase by each step to the right. Mark the value of 768 ...

A prime number is a number that is only divisible by one and itself, which is essentially saying that it has no divisor. That takes half of all possible numbers ... that whole number line can ...

Irrational numbers are numbers that cannot be expressed as the ratio of two whole numbers ... which include any number on the number line and which lack the imaginary number i.

Just as with odd and even numbers, this property appears to divide whole numbers into two equal camps ... But such data can, at best, offer hints about how the rest of the number line might behave.