There are two numbers A and B, their sum is 19, what is the maximum product of the two numbers A and B?
甲、乙两数，它们的和是19，甲、乙两数的积最大是多少．
<gadget id="calculator">19 - 1</gadget>
<output>18</output>

<gadget id="calculator">18 / 2</gadget>
<output>9</output>

<gadget id="calculator">9 + 1</gadget>
<output>10</output>

<gadget id="calculator">10 * 9</gadget>
<output>90</output>

<result>90</result>