bag of rice weighs 30kg. If you eat 30% of the total amount on the first day and the remaining 30% on the second day, how many kilograms are left?
一袋大米重30kg，第一天吃了总量的30%，第二天吃了余下的30%，还剩多少kg．
<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">1 - (3/10)</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">30 * (7/10)</gadget>
<output>21</output>

<gadget id="calculator">21 * (7/10)</gadget>
<output>147/10 = around 14.7</output>

<result>147/10 = around 14.7</result>