uses crt;

var a,b,c,d,tu,mau: integer; 

function uncln(m,n: integer): integer;

begin

while m<>n do

if m>n then m:=m-n else n:=n-m;

ucln:=m;

end;

begin

clrscr;

write ('nhap a: ');  readln (a);

write ('nhap b: ');  readln (b);

write ('nhap c: ');  readln (c);

write ('nhap d: ');  readln (d);

writeln ('a/ Hai phan so vua nhap: ',a,'/',b,' va ',c,'/',d);

tu:=a*d+c*b;

mau:=b*d;

tu:=tu div ucln(tu,mau);

mau:=mau div ucln(tu,mau);

writeln ('Tong 2 phan so la: ',tu,'/',mau);

readln;

end.

$#Trumtinhoc$

#include<bits/stdc++.h>
using namespace std;
int main(){
int a,b,c,d;
cin>>a>>b>>c>>d;
cout<<a<<"/"<<b<<endl<<c<<"/"<<d<<endl;
int mau_so=(b*d)/(__gcd(b,d));
int tu_so = a*(mau_so/b)+c*(mau_so/d);
int u = __gcd(tu_so,mau_so);
tu_so=tu_so/u;
mau_so=mau_so/u;
cout<<a<<"/"<<b<<" + "<<c<<"/"<<d<<" = "<<tu_so<<"/"<<mau_so;
}