Add 8.4 to the difference between 8.4 and 16, and divide the sum by 4. What is the quotient?
8.4加上8.4与16的差，所得的和除以4，商是多少？
<gadget id="calculator">16 - 8.4</gadget>
<output>7.6</output>

<gadget id="calculator">8.4 + 7.6</gadget>
<output>16</output>

<gadget id="calculator">16 / 4</gadget>
<output>4</output>

<result>4</result>