<P> i.e., the real numbers are an ordered group under addition . </P> <P> The properties that deal with multiplication and division state: </P> <Ul> <Li> For any real numbers, a, b and non-zero c: <Ul> <Li> If c is positive, then multiplying or dividing by c does not change the inequality: <Ul> <Li> If a ≥ b and c> 0, then ac ≥ bc and a / c ≥ b / c . </Li> <Li> If a ≤ b and c> 0, then ac ≤ bc and a / c ≤ b / c . </Li> </Ul> </Li> <Li> If c is negative, then multiplying or dividing by c inverts the inequality: <Ul> <Li> If a ≥ b and c <0, then ac ≤ bc and a / c ≤ b / c . </Li> <Li> If a ≤ b and c <0, then ac ≥ bc and a / c ≥ b / c . </Li> </Ul> </Li> </Ul> </Li> </Ul> <Li> For any real numbers, a, b and non-zero c: <Ul> <Li> If c is positive, then multiplying or dividing by c does not change the inequality: <Ul> <Li> If a ≥ b and c> 0, then ac ≥ bc and a / c ≥ b / c . </Li> <Li> If a ≤ b and c> 0, then ac ≤ bc and a / c ≤ b / c . </Li> </Ul> </Li> <Li> If c is negative, then multiplying or dividing by c inverts the inequality: <Ul> <Li> If a ≥ b and c <0, then ac ≤ bc and a / c ≤ b / c . </Li> <Li> If a ≤ b and c <0, then ac ≥ bc and a / c ≥ b / c . </Li> </Ul> </Li> </Ul> </Li>

When do we use greater than or equal to