Uncle Zhang practiced shooting. He fired a total of 40 bullets, with a hit rate of 80%. How many bullets missed the target?
张叔叔练习打靶，共打了40发子弹，命中率为80%，脱靶的子弹有多少发？
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 - (4/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">40 * (1/5)</gadget>
<output>8</output>

<result>8</result>