In a subtraction formula, the sum of the minuend, the subtrahend and the difference is 14.4, and the difference is twice the subtrahend. What is the difference?
在一个减法算式里，被减数、减数与差的和是14.4，差是减数的2倍，差是多少
<gadget id="calculator">2 + 1</gadget>
<output>3</output>

<gadget id="calculator">14.4 / 2 / 3</gadget>
<output>2.4</output>

<gadget id="calculator">2.4 * 2</gadget>
<output>4.8</output>

<result>4.8</result>