Math Problem Solver

\[ 7 + 7 - \frac{7}{7} + 7 = 20 \]

The sum can be computed by rewriting each term over a common denominator, where the least common denominator of \(\frac{7}{1}\), \(\frac{7}{1}\), \(\frac{-7}{7}\), and \(\frac{7}{1}\) is \(7\). \[ \begin{aligned} 7 + 7 - \frac{7}{7} + 7 &= \frac{7 \cdot 7}{1 \cdot 7} + \frac{7 \cdot 7}{1 \cdot 7} + \frac{-7 \cdot 1}{7 \cdot 1} + \frac{7 \cdot 7}{1 \cdot 7} \\ &= \frac{49 + 49 + -7 + 49}{7} \\ &= \frac{140}{7} \\&= 20 \end{aligned} \]