Students stand in line to do exercises, the boys stand in five rows, 28 people in each row. The number of girls is half of boys, how many girls are there?
同学们站队做操，男生站五行，每行28人．女生人数是男生的一半，女生有多少人．
<gadget id="calculator">5 / 2</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">28 * (5/2)</gadget>
<output>70</output>

<result>70</result>