The dividend is 4, the quotient is 1.8, and the remainder is 1.3. What is the divisor?
被除数是4，商是1.8，余数是1.3，除数是多少．
<gadget id="calculator">4 - 1.3</gadget>
<output>2.7</output>

<gadget id="calculator">2.7 / 1.8</gadget>
<output>1.5</output>

<result>1.5</result>