It is known that the product of two factors is 3.9, one factor is enlarged by 10 times, and the other factor is reduced by 100 times, what is the product?
已知两个因数的积是3.9，一个因数扩大10倍，另一个因数缩小100倍，积是多少．
<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">3.9 * (1/10)</gadget>
<output>0.39</output>

<result>0.39</result>