\(\left(\frac{575757}{424242}+\frac{575757}{565656}+\frac{575757}{727272}\right)\cdot18\)
\(=\left(\frac{19}{14}+\frac{57}{56}+\frac{19}{24}\right)\cdot18\)
\(=\left(\frac{228+171+133}{168}\right)\cdot18\)
\(=\frac{532}{168}\cdot18\)
\(=\frac{19}{6}\cdot8\)
\(=\frac{76}{3}\)
\(\left(\frac{575757}{424242}+\frac{575757}{565656}+\frac{575757}{727272}\right)\cdot18=\left(\frac{57}{42}+\frac{57}{56}+\frac{57}{72}\right)\cdot18=\frac{57}{42}\cdot18+\frac{57}{56}\cdot18+\frac{57}{72}\cdot18=\frac{171}{7}+\frac{513}{28}+\frac{57}{4}=\frac{684}{28}+\frac{513}{28}+\frac{399}{28}=\frac{1596}{28}=57\)
