What is the difference between 7.8 and the product of 2.4 and 1.5?
7.8减去2.4与1.5的积，差是多少？
<gadget id="calculator">2.4 * 1.5</gadget>
<output>3.6</output>

<gadget id="calculator">7.8 - 3.6</gadget>
<output>4.2</output>

<result>4.2</result>