There are 81 members in the school chorus, of which boys account for 2/9 of the total number. How many boys are there?
学校合唱队有81人，其中男生占总人数的(2/9)，男生有多少人？
<gadget id="calculator">2 / 9</gadget>
<output>2/9 = around 0.222222</output>

<gadget id="calculator">81 * (2/9)</gadget>
<output>18</output>

<result>18</result>