(1/4) times a number is equal to the difference between 40 minus 15, what is this number? (solution with equation)
一个数的1(1/4)倍等于40减15的差，这个数是多少？(用方程解答)
<gadget id="calculator">40 - 15</gadget>
<output>25</output>

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

<gadget id="calculator">25 * (4/5)</gadget>
<output>20</output>

<result>20</result>