From Förberedande kurs i matematik 1

Individually, \displaystyle 3^{1.4} and \displaystyle 3^{0.6} are difficult to calculate, but when multiplied together

\displaystyle 3^{1.4}\centerdot 3^{0.6}=3^{1.4+0.6}=3^{2}=3\centerdot 3=9.

on using the power rules.