\(=\dfrac{637.\left(526+1\right)-189}{526.637+448}=\dfrac{637.526+637-189}{526.637+446}=\dfrac{637.526+448}{526.637+448}=1\)
\(\left(637.527-189\right):\left(526.637+448\right)\)
\(=\left(335699-189\right):\left(335062+448\right)\)
\(=335510:335510\)
\(=1\)