Perform four arithmetic operations on the four numbers 1, 2, 3, and 8, and use each number only once to make the result equal to 24.
1、2、3、8这四个数字进行四则运算，每个数只用一次，使其结果等于24．
<gadget id="calculator">1 + 3</gadget>
<output>4</output>

<gadget id="calculator">8 - 2</gadget>
<output>6</output>

<gadget id="calculator">4 * 6</gadget>
<output>24</output>

<result>24</result>