Simple calculator in Java

Calc.java

import java.util.*

//Simple calculator

public class calc
{
    public static void main(String[] args)
    {
        Scanner in = new Scanner(System.in);
        double a, b, c = 0.0;

        System.out.print("Enter the first number \n");
        a = in.nextDouble();
        System.out.print("And enter second  \n");
        b = in.nextDouble();
        System.out.print("Choose the operation  " +
              "\n1.Addition" +
        		"\n2.Subtraction" +
        		"\n3.Multiplication" +
        		"\n4.Division" +
        		"\n5.Power" +
        		"\n#Please enter the number of operation \n");
        double somethin = in.nextDouble();
        double addition = 1;
        double subtraction = 2;
        double multiplication = 3;
        double division = 4 ;
        double power = 5;
        if (somethin == addition) {
        	c = a + b;  
        	System.out.println(a + " + " + b + " = " + c);  }
        else if (somethin == subtraction)  {
        	c = a - b;  
        	System.out.println(a + " - " + b + " = " + c);	}
        else if (somethin == multiplication)	{
        	c = a * b;   
        	System.out.println(a + " * " + b + " = " + c);	}
        else if (somethin == division)   {
        	c = a / b;  
        	System.out.println(a + " / " + b + " = " + c);	}
        else if (somethin == power)	{
        	System.out.println("Enhance A or B?" +
        			"\n1.A" +
        			"\n2.B");
        	double enhance = in.nextDouble();
        	double first = 1;
        	double second = 2;
        		if (enhance == first) {
        			System.out.println(Math.pow(a, 2)); }	
        		else if (enhance == second); {
        			System.out.println(Math.pow(b, 2)); }
        
        }
    }
}

Best calculator on GitHub is here. Click on the link given below.
https://github.com/akash-mahanty/calculator

Pls can you make comments to explain the code?

Very inefficient. And grammatical mistakes in code.