The product of two factors is 400, one of the factors is reduced to (1/10) of the original number, and the other factor is expanded to 100 times of the original number, what is the product?
两个因数的积是400，其中一个因数缩小到原数的(1/10)，另一个因数扩大到原数的100倍，积是多少．
<gadget id="calculator">40 * 100</gadget>
<output>4_000</output>

<result>4_000</result>