A bag of rice ate 60 kg on the second day, 20 kg more than the first day (4/5), how many kg did you eat on the first day?
一袋大米第二天吃了60千克，比第一天吃的(4/5)多20千克，第一天吃了多少千克？
<gadget id="calculator">60 - 20</gadget>
<output>40</output>

<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">40 / (4/5)</gadget>
<output>50</output>

<result>50</result>