Math Problem Solver

\[ \frac{21}{6} - \frac{4}{5} = \frac{27}{10} = 2.7 \]

The sum can be computed by rewriting each term over a common denominator, where the least common denominator of \(\frac{21}{6}\) and \(\frac{-4}{5}\) is \(30\). \[ \begin{aligned} \frac{21}{6} - \frac{4}{5} &= \frac{21 \cdot 5}{6 \cdot 5} + \frac{-4 \cdot 6}{5 \cdot 6} \\ &= \frac{105 + -24}{30} \\ &= \frac{81}{30} \\&= \frac{27}{10} \end{aligned} \]