The sum of 3 2.4 plus 4 times of a certain number is 10, what is the certain number?
3个2.4的和加上某数的4倍得10，某数是多少？
<gadget id="calculator">2.4 * 3</gadget>
<output>7.2</output>

<gadget id="calculator">10 - 7.2</gadget>
<output>2.8</output>

<gadget id="calculator">2.8 / 4</gadget>
<output>0.7</output>

<result>0.7</result>