Trying to add fractions while also printing LCD

I'm a beginner trying to figure out this program of adding fractions while also making their output print the result in it's lowest common denominator form. Running it in this form never runs properly...

using namespace std;

class Fraction { //Creates class Fraction

private: //Makes data members private

int num;
int denm;

 };
 int main()
{

int num;
int denm;
int num2;
int denm2;
int plus;
int plus2;


cout << "Please enter the numerator and denominator of the first fraction: " << endl; 
cin >> num >> denm; 

cout << "Please enter the numerator and denominator of the second fraction: " << endl;
cin >> num2 >> denm2;


plus = num*denm2 + denm*num2;
plus2 = denm*denm2;

cout << num << "/" << denm << " + " << num2 << "/" << denm2 << " = " << plus << "/" << plus2;

cout << "Hit 'enter' to exit..." << endl;

}