20^98/((25^48)*16^49)

$$\frac{20^{98}}{25^{48}\times 16^{49}}=\frac{4^{98}\times 5^{98}}{5^{2\times48}\times 4^{2\times49}}}=\frac{4^{98}\times5^{98}}{5^{96}\times4^{98}}=5^{98-96}=5^2=25$$

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