var calculator =
{
    save: function(newA,newB)
    {
        this.a = newA;
        this.b = newB;
    },

    sum: function()
    {
      return this.a + this.b;
    },

    multiply: function()
    {
    return this.a * this.b;
    },

    sqrt: function()
    {
    return Math.sqrt(this.a + this.b);
    },

    pow: function()
    {
    return Math.pow(this.b, this.a);
    },

    avg: function()
    {
    var sum = 0, result = 0;
    sum =this.a + this.b;
    result = sum/2;
    console.log(result);
    }
};

calculator.save(2,3);
console.log( calculator.sum() );
console.log( calculator.multiply() );
console.log( calculator.sqrt() );
console.log( calculator.pow() );
calculator.avg();