java BigInteger and BigDecimal

/* java BigInteger and BigDecimal */

package myFirst;
import java.math.BigInteger;
import java.math.RoundingMode;
import java.math.BigDecimal;

import java.util.*;
public class mathfun {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner sc = new Scanner(System.in);
        BigInteger num = sc.nextBigInteger();
        BigInteger num2 = sc.nextBigInteger();
        BigInteger Add,Sub,Mul,Div,Mod;
        Add = num.add(num2);
        Sub = num.subtract(num2);
        Mul = num.multiply(num2);
        Div = num.divide(num2);
        Mod = num.mod(num2);
        System.out.println(Add + " "+ Sub + " " + Mul +" " +Div +" "+ Mod );
        BigInteger sum = new BigInteger("0");
        for(int i = 1;i<=10005;i++) {
            BigInteger x = new BigInteger(Integer.toString(i));
            sum =  sum.add(Add.mod(x));
        }
        System.out.println(sum);

        if(sum.compareTo(new BigInteger("800"))>=0)System.out.println("YES");
        if(sum.compareTo(Add)>=0)System.out.println("YES");
        for(BigInteger i = BigInteger.ONE;i.compareTo(new BigInteger("10"))<=0;i = i.add(BigInteger.ONE)) {
            System.out.println(i);

        }

        sum = sum.gcd(Add);
        boolean tr;
        tr = sum.isProbablePrime(1);
        tr = new BigInteger("7").isProbablePrime(1);

        System.out.println(tr);

        BigDecimal b = new BigDecimal("100");

        System.out.println(b.divide(new BigDecimal("3"),5,RoundingMode.CEILING));

        System.out.println("Mod Pow = " + a.modPow(b, new BigInteger("10000009"))); // returns a^b mod 10000009

System.out.println("Modulus Inverse = " + a.modInverse(b)); //  a^-1 mod b, this throws ArithmeticException - b ≤ 0, or 'a' BigInteger has no multiplicative inverse mod b (that is, this 'a' is not relatively prime to 'b'

System.out.println("GCD = " + a.gcd(b)); // finds gcd, how cool is this?

System.out.println( a.isProbablePrime(15)? true: false ); // checks if the number is probably prime or not , uses th Miller-Rabin primality test and with certainty of about 15 it is good enough to produce correct results.

System.out.println("Next prime after" + a + " is " + a.nextProbablePrime());// Returns the first integer greater than a that is probably prime.





    }

}