Using 80 square decimeters of fabric to make a 400 square centimeter square handkerchief, how much can it be made at most?
用80平方分米方布料，做成400平方厘米方手绢，最多能做成多少
<gadget id="calculator">80 * 100</gadget>
<output>8_000</output>

<gadget id="calculator">8_000 / 400</gadget>
<output>20</output>

<result>20</result>