If there are 2 zeros at the end of the factor and 3 zeros at the end of the factor, how many zeros does their product have at least?
如果因数的末尾有2个零，因数的末尾有3个零，它们的积至少有多少个零．
<gadget id="calculator">2 + 3</gadget>
<output>5</output>

<result>5</result>