Need help with simple code for calculating interest...not compound....yet. Can not figure out what code is needed to change the -double percent- to a -decimal-.

Giving me a error:
------ Build started: Project: Practice_Work, Configuration: Debug Win32 ------
Practice_Work.cpp
Practice_Work.cpp(24): error C2440: '=' : cannot convert from 'System:ecimal' to 'double'
No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

Here is the Code i have written so far:

// Practice_Work.cpp : main project file.
// calculating intrest over one fixed period

#using <mscorlib.dll>
#include <iostream>
using namespace System;
using namespace std;

int main()
{

//declaring variables

double number= 0.0;
double percent= 0.0;
double difference= 0.0;
double sum= 0.0;

//Algorithms: assigning intergers to variables

Console::WriteLine("Enter Amount: ");
number= Convert::ToDouble(Console::ReadLine());
Console::WriteLine("Enter Intrest Rate: ");
percent= Convert::ToDouble(Console::ReadLine());
percent= Convert::ToDecimal(percent);


//Calculations for solving the algorithm

difference= number*percent;
sum= number + difference;

//Printing out the results

Console::WriteLine("Total amount after intrest equals: ",Convert::ToString(sum));


cin.get();
return 0;

}