Code

uses crt;
function gcd(a,b:integer): integer;
var tmp: integer;
begin
    while b <> 0 do
    begin
        tmp := b;
        b := a mod b;
        a := tmp;
    end;
    gcd := a;
end;
var a,b,c,d,tmp: integer;
begin
read(a,b,c,d);
if gcd(a,b) <> 1 then
begin
    a := a div gcd(a,b);
    b := b div gcd(a,b);
end;
if gcd(c,d) <> 1 then
begin
    c := c div gcd(c,d);
    d := d div gcd(c,d);
end;
// Tinh Tong
tmp := b * d;
if gcd(a+c, tmp) <> 1 then
    writeln((a*d+c*b) div gcd(a*d+c*b, tmp), ' ', tmp div gcd(a*d+c*b, tmp))
else writeln(a*d+c*b,' ',tmp);
// Tinh hieu
tmp := b * d;
if gcd(a*d-c*b, tmp) <> 1 then
    writeln((a*d-c*b) div gcd(a*d-c*b, tmp), ' ', tmp div gcd(a*d-c*b, tmp))
else writeln(a*d-c*b,' ',tmp);
// Tich tich
if gcd(a*c, b*d) <> 1 then
    writeln((a*c) div gcd(a*c, b*d),' ',(b*d) div gcd(a*c, b*d))
else writeln(a*c,' ',b*d);
// Tich thuong
if gcd(a*d, b*c) <> 1 then
    writeln((a*d) div gcd(a*d, b*c),' ',(b*c) div gcd(a*d, b*c))
else writeln(a*d,' ',b*c);
end.

uses crt;
var a,b,c,d: integer;
function gcd(a,b: integer): integer;
begin
    while a<>b do if a>b then a:=a-b else b:=b-a;
    exit(a);
end;
begin
clrscr;
    readln(a,b,c,d);
    writeln((a*d+c*b)/gcd((a*d+c*b),b*d):0:0,' ',b*d/gcd((a*d+c*b),b*d):0:0);
    writeln((a*d-c*b)/gcd((a*d-c*b),b*d):0:0,' ',b*d/gcd((a*d-c*b),b*d):0:0);
    writeln(a*c/gcd(a*c,b*d):0:0,' ',b*d/gcd(a*c,b*d):0:0);
    write(a*d/gcd(a*d,b*c):0:0,' ',b*c/gcd(a*d,b*c):0:0);
    readln
end.