2 times of 3.7 is 0.4 less than 25% of a number, find this number (use equation solution)
3.7的2倍比一个数的25%少0.4，求这个数(用方程解)
<gadget id="calculator">3.7 * 2</gadget>
<output>7.4</output>

<gadget id="calculator">0.4 + 7.4</gadget>
<output>7.8</output>

<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">7.8 / (1/4)</gadget>
<output>31.2</output>

<result>31.2</result>