What is the angle in degrees that is 20% less than the straight angle?
比平角少20%的角是多少度．
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">180 * (4/5)</gadget>
<output>144</output>

<result>144</result>