Kiwiland, I think yours is the only answer close to right. But then, you could code it to whatever you want, that way anything can be proven right. Sarala, I am not sure if you already know your assesment is wrong or not, but neverthless, pardon my explanation: Note the comment after the dots. LHS =22 .........given =2*4^1+2*4^0 (Converting in Foral numbering system) .....okay so far. =10 .......... agree, that's the decimal representation of 22. =1*4^1+0*4^0 (Converting in Foral numbering system) .........now wait a minute!!! what are you doing? Here u are converting 10 to decimal as if 10 was a foral already. Remember it never was foral as in above operation, you actually converted foral to decimal. End of story. =4 .........u will never get this far. Instead of converting 10 to foral, the only thing that is allowed is finding the foral representation of 10. =2+2 =RHS It should be a waste of time to try to find a way to fix this equation. I'd go with Kiwiland's answer.