The bottom angle of the red scarf worn by Lin Ming is 30°. What is the top angle of this red scarf?
林明身上佩戴的红领巾，它的一个底角是30°，这条红领巾的顶角是多少度？
<gadget id="calculator">30 * 2</gadget>
<output>60</output>

<gadget id="calculator">180 - 60</gadget>
<output>120</output>

<result>120</result>