Calculate (4*10**5)*(5*10**4)=how much.
计算(4*10**5)*(5*10**4)=多少．
<gadget id="calculator">10 ** 5</gadget>
<output>100_000</output>

<gadget id="calculator">4 * 100_000</gadget>
<output>400_000</output>

<gadget id="calculator">10 ** 4</gadget>
<output>10_000</output>

<gadget id="calculator">5 * 10_000</gadget>
<output>50_000</output>

<gadget id="calculator">400_000 * 50_000</gadget>
<output>20_000_000_000</output>

<result>20_000_000_000</result>