A and B are the reciprocals of each other. If the decimal point of B is moved two places to the right, it is 250. What is A's number?
甲、乙两数互为倒数，将乙数的小数点向右移两位是250，甲数是多少．
<gadget id="calculator">1 / 2.5</gadget>
<output>0.4</output>

<result>0.4</result>