Divide a circle into 8 parts on average, Xiaohong has already painted 3 of them, and how many more parts need to be painted to fill it up.
把一个圆平均分成8份，小红已经涂了其中3份，需再涂多少份就涂满了．
<gadget id="calculator">8 - 3</gadget>
<output>5</output>

<result>5</result>