#include <iostream>

using namespace std;

struct fraction
{ int top, bot; };

int gcd_version1(int a, int b)   // takes a long time for big numbers
{ int sml;
  if (a < b)
    sml = a;
  else
    sml = b;
  for (int d = sml; d > 1; d -= 1)
  { if (a % d == 0 &&
        b % d == 0)
      return d; }
  return 1; }

int gcd(int a, int b)    // Euclid's algorithm from about 300 BC
{ while (b != 0)
  { int t = b;
    b = a % b;
    a = t; }
  return a; }

fraction norm(fraction X)
{ int d = gcd(X.top, X.bot);
  if (d == 1)
    return X;
  fraction R;
  R.top = X.top / d;
  R.bot = X.bot / d;
  return R; }

fraction add(fraction A, fraction B)
{ fraction R;
  R.top = A.top*B.bot + B.top*A.bot;
  R.bot = A.bot*B.bot;
  return norm(R); }

fraction sub(fraction A, fraction B)
{ fraction R;
  R.top = A.top*B.bot - B.top*A.bot;
  R.bot = A.bot*B.bot;
  return norm(R); }

fraction mul(fraction A, fraction B)
{ fraction R;
  R.top = A.top*B.top;
  R.bot = A.bot*B.bot;
  return norm(R); }

fraction div(fraction A, fraction B)
{ fraction R;
  R.top = A.top*B.bot;
  R.bot = A.bot*B.top;
  return norm(R); }

void print(fraction X)
{ if (X.top == 0)
    cout << "0"; 
  else if (X.bot == 1)
    cout << X.top;
  else if (X.top > X.bot)
    cout << " " << X.top/X.bot << "+" << X.top%X.bot << "/" << X.bot << " ";
  else
    cout << " " << X.top << "/" << X.bot << " "; }

int main()
{ while (true)
  { fraction a, b;
    cout << "Enter A's top and bottom: ";
    cin >> a.top >> a.bot;
    cout << "Enter B's top and bottom: ";
    cin >> b.top >> b.bot;

    cout << "A + B = ";
    print(add(a, b));
    cout << "\n";

    cout << "A - B = ";
    print(sub(a, b));
    cout << "\n";

    cout << "A * B = ";
    print(mul(a, b));
    cout << "\n";

    cout << "A / B = ";
    print(div(a, b));
    cout << "\n"; } }