随机生成300道四则运算

package work;

public class mathwork {
    public static void subject(Object obj) {
        System.out.println(obj);
        }
        public static void main(String[] args) {
        subject("四则运算练习题：");
        int count = 0;
        for (int i = 0; i < 300; i++) {
        int d1 = (int) ((Math.random()) * 100);
        int d2 = (int) ((Math.random()) * 100);
        int k = (int) ((Math.random()) * 100);
        int k2 = (int) ((Math.random()) * 100);
        int k3 = (int) ((Math.random()) * 100);
        int k4 = (int) ((Math.random()) * 100);
        int x = 1;
        if (0 <= k && k < 12)
        x = 1;
        else if (12 <= k && k < 24)
        x = 2;
        else if (24 <= k && k < 36)
        x = 3;
        else if (36 <= k && k < 48)
        x = 4;
        else if (48 <= k && k < 60)
        x = 5;
        else if (60 <= k && k < 72)
        x = 6;
        else if (72 <= k && k < 84)
        x = 7;
        else
        x = 8;
        switch (x) {
        case 1:
        subject(d1 + "+" + d2 + "=");
        break;
        case 2:
        jiafa(d1, d2);
        break;
        case 3:
        subject(d1 + "*" + d2 + "=");
        break;
        case 4:
        chufa(d1, d2);
        break;
        case 5:
        subject(zhenfenshu(k, k2) + "+" + zhenfenshu(k3, k4) + "=");
        break;
        case 6:
        subject(zhenfenshu(k, k2) + "-" + zhenfenshu(k3, k4) + "=");
        break;
        case 7:
        subject(zhenfenshu(k, k2) + "*" + zhenfenshu(k3, k4) + "=");
        break;
        case 8:
        subject(zhenfenshu(k, k2) + "/" + zhenfenshu(k3, k4) + "=");
        break;
        default:
        subject("stop,stop,stop");
        break;
        }
        count++;
        }
        subject("以上共有" + count + "四则运算练习题！");
        }
        public static void jiafa(int a, int b) {
        if (a > b)
        subject(a + "-" + b + "=");
        else {
        subject(b + "-" + a + "=");
        }
        }
        public static void chufa(int a, int b) {
        if (b > 0)
        subject(a + "/" + b + "=");
        else {
        b = b + 10;
        subject(a + "/" + b + "=");
        }
        }
        public static String zhenfenshu(int a, int b) {
        if (a <= b)
        return a + "/" + b;
        else
        return b + "/" + a;
        }
        }

先写出随机生成数字的代码，然后编写逻辑代码进行加减乘除的运算。

这是运行之后的结果。