The result of a product of real numbers is not changed if the order of the factors is modified.

The result of an addition between real numbers is not changed if the order of the terms is modified.

The product in which the factors are a real number and a sum of real numbers can be done by multiplying the first factor by each term of the second and summing the results.

There are real numbers that have two or more inverse elements.

For each real number a, there is only one real number - a whose sum a + (– a) is equal to zero.