Dear all, Mmany thanx for your explanations. I have one solution which goes as follows: Lets suppose in Foral Numbering system where we have only 0, 1, 2 & 3. LHS =22 =2*4^1+2*4^0 (Converting in Foral numbering system) =10 =1*4^1+0*4^0 (Converting in Foral numbering system) =4 =2+2 =RHS I hope this is one of the many solutions.