策略模式和简单工厂模式

策略模式和简单工厂模式有什么不同额？最近在学习设计模式，遇到这两种模式，有点儿迷糊？

简单工厂模式：

public class Operation
{
public static double GetResult(double numberA, double numberB, string operate)
{
double result = 0;
switch (operate)
{
case "+":
result = numberA + numberB;
break;
case "-":
result = numberA + numberB;
break;
case "*":
result = numberA + numberB;
break;
case "/":
if (numberB != 0)
result = numberA + numberB;
break;
}
return result;
}

private double _numberA = 0;

public double NumberA
{
get { return _numberA; }
set { _numberA = value; }
}

private double _numberB = 0;

public double NumberB
{
get { return _numberB; }
set { _numberB = value; }
}

public virtual double GetResult()
{
double result = 0;
return result;
}
}

class OperationAdd : Operation
{
public override double GetResult()
{
double result = 0;
result = NumberA + NumberB;
return result;
}
}

class OperationSub : Operation
{
public override double GetResult()
{
double result = 0;
result = NumberA - NumberB;
return result;
}
}

class OperationMul : Operation
{
public override double GetResult()
{
double result = 0;
result = NumberA * NumberB;
return result;
}
}

class OperationDiv : Operation
{
public override double GetResult()
{
double result = 0;
result = NumberA * NumberB;
return result;
}
}

public class OperationFactory
{
public static Operation CreateOperate(string operation)
{
Operation oper = null;
switch (operation)
{
case "+":
oper = new OperationAdd();
break;
case "-":
oper = new OperationSub();
break;
case "*":
oper = new OperationMul();
break;
case "/":
oper = new OperationDiv();
break;
}
return oper;
}
}

策略模式：

abstract class CashSuper
{
public abstract double AcceptCash(double money);
}

class CashNormal : CashSuper
{
public override double AcceptCash(double money)
{
return money;
}
}

class CashRebate : CashSuper
{
private double moneyRebate = 1;
public CashRebate(double moneyRebate)
{
this.moneyRebate = moneyRebate;
}

public override double AcceptCash(double money)
{
return money * moneyRebate;
}
}

class CashReturn : CashSuper
{
private double moneyCondition = 0.0;

private double moneyReturn = 0.0;

public CashReturn(double moneyCondition, double moneyReturn)
{
this.moneyCondition = moneyCondition;
this.moneyReturn = moneyReturn;
}

public override double AcceptCash(double money)
{
double result = money;
if (money >= moneyCondition)
result = money - Math.Floor(money / moneyCondition) * moneyReturn;
return result;
}
}

class CashContext
{
private CashSuper cs;

public CashContext(string type)
{
switch (type)
{
case "正常收费":
cs = new CashNormal();
break;
case "满300返100":
cs = new CashReturn(300, 200);
break;
case "打8折":
cs = new CashRebate(0.8);
break;
}
}

public double GetResult(double money)
{
return cs.AcceptCash(money);
}
}

难道仅仅是他们之间的耦合度降低了吗？