Задача 2.

a) Let $A$ be the set of one-digit natural (positive integer) numbers. Define its subset ${2,4,6,8}$ using the notation from the definition above. b) Let $A$ be the set of all cities in the USA. List all the elements of the following subset {$x \in A$ | the population of $x$ is more than 1 000 000 as of 01/01/2015}