What should be added to
Â
∵ (The required number) +
 ∴  (The required number) = Â
           Â
              Â
       (∵ LCM of 21 and 7 is 21 and 21 +7=3)
         Â
      Â
                 Â
Subtract Â
                                           Â
                                            Â
                                             Â
The sum of two rational numbers is . if one of them is find the other.
 ∵   + ( A rational number) =Â
 ∴   (The required rational number) =
                            Â
                                           ( ∵ LCM of 5 and 20 is 20)
                                        Â
                            Â
                                         Â