The turnover of a shopping mall in August is 4.2 million yuan, and the business tax is 5% of the turnover. How much is it necessary to pay?
某商场八月份营业额是420万元，按营业额的5%缴纳营业税，要缴纳多少万元？
<gadget id="calculator">5 / 100</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">420 * (1/20)</gadget>
<output>21</output>

<result>21</result>