In the formula 11*20*29*38*...*200, the difference between two adjacent factors is equal to 9, so what is the number of consecutive zeros at the end of the product.
在算式11*20*29*38*…*200中，相邻两个因数的差都等于9，那么这个乘积的末尾连续的零的个数等于多少．
<gadget id="calculator">4 + 2</gadget>
<output>6</output>

<result>6</result>