public class math {
    public static void main(String[] args) {

        String[] operate=new String[]{"+","-","×","÷"};
        int[] numbers=new int[300];

        for(int i=1;i<=300;i++){
            numbers[i-1]=i;
        }
        Random r=new Random();

        for(int i=0;i<300;i++){

            System.out.println(numbers[r.nextInt(300)]+operate[r.nextInt(4)]+numbers[r.nextInt(300)]+"=");
        }
    }
}

用Java实现四则运算