5,48 * 10^-4 = 5,48 * 1/10^4 = 5,48 * 1/10000 = 0,000548

[tex]5.48 \times {10}^{ - 4} = \frac{5.48}{ {10}^{4} } = \frac{548}{100} \times \frac{1}{10 {}^{4} } = \frac{137}{25} \times \frac{1}{ {10}^{4} } = \frac{137}{250000} = 0.000548[/tex]