The kitten went fishing by the river, catching 9 cats a day in sunny days and 5 cats a day in rainy days, for a total of 6 days, with an average of 7 cats a day. So, how many days are sunny?
小猫去河边钓鱼，晴天每天钓9条，雨天每天钓5条，一共钓了6天，平均每天钓7条．那么，有几天晴天？
<gadget id="calculator">6 * 7</gadget>
<output>42</output>

<gadget id="calculator">5 * 6</gadget>
<output>30</output>

<gadget id="calculator">42 - 30</gadget>
<output>12</output>

<gadget id="calculator">9 - 5</gadget>
<output>4</output>

<gadget id="calculator">12 / 4</gadget>
<output>3</output>

<result>3</result>