Монгол Бодлогын Сан

Заавар: $\left(3\overset{I}{\mathstrut+}\dfrac14\right)\overset{III}{\mathstrut\cdot}\left(286\dfrac{2}{13}\overset{II}{\mathstrut-}285\dfrac{1}{13}\right)$ байна.

Бодолт: I. $3+\dfrac14=\dfrac{3\cdot4+1}{4}=\dfrac{13}{4}$;

II. $286\dfrac{2}{13}-285\dfrac{1}{13}=(286-285)+\Big(\dfrac{2}{13}-\dfrac{1}{13}\Big)=1\dfrac1{13}=\dfrac{13+1}{13}=\dfrac{14}{13}$;

III. $\dfrac{13}{4}\cdot\frac{14}{13}=\dfrac{14}{4}=\dfrac72=3.5$