There is a barrel of oil, 25% of the total amount is taken out for the first time, and 2kg (3/8) of the total amount is taken out for the second time, so there is still 7kg left. How many kilograms does this barrel of oil have? (solution by equation)
有一桶油，第一次取出总数的25%，第二次取出总数的(3/8)还多2kg，这时还剩7kg，这桶油原有多少千克？(用方程解)
<gadget id="calculator">2 + 7</gadget>
<output>9</output>

<gadget id="calculator">5 / 8</gadget>
<output>5/8 = around 0.625</output>

<gadget id="calculator">1 - (5/8)</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">9 / (3/8)</gadget>
<output>24</output>

<result>24</result>