3. The number of trailing zeros in 2006! is ( )
A. 499
B. 500
C. 501
D. 502
3. B Hint: The number of trailing 0's in 2006! is the exponent of 5, and $L_{5}(2006!)=\left[\frac{2006}{5}\right]+$ $\left[\frac{2006}{5^{2}}\right]+\left[\frac{2006}{5^{3}}\right]+\left[\frac{2006}{5^{4}}\right]=500$.