The formula 1*2*3*4*5*6*7...*23*24*25 is equal to a large product, how many consecutive zeros are there at the end of the product?
算式1*2*3*4*5*6*7…*23*24*25等于一个很大的积，请问，积的末尾有多少个连续的零．
<gadget id="calculator">25 / 5</gadget>
<output>5</output>

<gadget id="calculator">25 / 25</gadget>
<output>1</output>

<gadget id="calculator">5 + 1</gadget>
<output>6</output>

<result>6</result>