1. Know-it-all told Don't-know-it that to convert kilolunes (a unit of mass used by the little people on the Moon) to kilograms, one needs to divide the mass in kilolunes by 4 and then decrease the obtained number by $4 \%$. Don't-know-it decided that to convert from kilograms to kilolunes, one should multiply the mass in kilograms by 4 and then increase the obtained number by 4\%. By what percentage of the correct value of the mass in kilolunes will he be wrong if he translates this way?

ANSWER: by $0.16 \%$.
Solution: One kilolun constitutes $0.25 * 0.96=0.24$ kg. Therefore, in one kilogram there are 25/6 kiloluns. If Nезнайка converts 1 kg, he will get $4 * 1.04=4.16$, which is $99,84 \%$ of $25 / 6$.