Simple Java Maths

public class Operators {
    public static void main(String[] args) {
        int answer; 
        System.out.println("ADDITION");
        int add = 20;
        System.out.println("Initial value: " + add);
        answer = add + 2;
        System.out.println("add + 2 = " + answer);
        answer = add;
        System.out.println("add = " + answer);
        System.out.println();
        System.out.println("SUBTRACTION");
        int sub = 15;
        System.out.println("Initial value: " + sub);
        System.out.println("sub - 4 = " + (sub - 4));
        System.out.println("sub = " + sub);
        System.out.println();
        System.out.println("MULTIPLICATION");
        int mult = 25;
        System.out.println("Initial value: " + mult);
        answer = mult * 3;
        System.out.println("mult * 3 = " + answer);
        answer = mult;
        System.out.println("mult = " + mult);
        System.out.println();
        System.out.println("DIVISION (INT)");
        int div_int = 15;
        System.out.println("Initial value: " + div_int);
        System.out.println("div_int / 2 = " + (div_int / 2));
        System.out.println("div_int = " + div_int);
        System.out.println();
        System.out.println("MODULO (REMINDER)");
        int rem = 5;
        System.out.println("Initial value: " + rem);
        answer = rem % 2;
        System.out.println("rem % 2 = " + answer);
        answer = rem;
        System.out.println("rem = " + answer);
        System.out.println();
        System.out.println("PREINCREMENT BY ONE");
        int pre_inc = 5;
        System.out.println("Initial value: " + pre_inc);
        System.out.println("++pre_inc   = " + (++pre_inc));
        System.out.println("pre_inc = " + pre_inc);
        System.out.println();
        System.out.println("PREDECREMENT BY ONE");
        int pre_dec = 5;
        System.out.println("Initial value: " + pre_dec);
        answer = --pre_dec;
        System.out.println("--pre_dec   = " + answer);
        answer = pre_dec;
        System.out.println("pre_dec = " + answer);
        System.out.println();
        System.out.println("POST INCREMENT BY ONE");
        int post_inc = 5;
        System.out.println("Initial value: " + post_inc);
        System.out.println("post_inc++   = " + (post_inc++));
        System.out.println("post_inc = " + post_inc);
        System.out.println();
        System.out.println("POSTDECREMENT BY ONE");
        int post_dec = 5;
        System.out.println("Initial value: " + post_dec);
        answer = post_dec--;
        System.out.println("post_dec--   = " + answer);
        answer = post_dec;
        System.out.println("post_dec = " + answer);
        System.out.println();
    }
}