- If 9 cows eat a piece of grass. Eat all the grass in 12 days, if 8 cows eat all the grass in 16 days. Now there are only 4 cows, and several more cows have been added from the 7th day, and all the grass has been eaten in another 6 days. Ask how many cows have been added?
-片草地如果9头牛吃．12天吃完所有的草，如果8头牛吃，16天吃完所有的草．现在开始只有4头牛，从第7天起又增加了若干头牛，再6天吃完所有草．问增加了多少头牛？
<gadget id="calculator">12 * 9</gadget>
<output>108</output>

<gadget id="calculator">16 * 8</gadget>
<output>128</output>

<gadget id="calculator">128 - 108</gadget>
<output>20</output>

<gadget id="calculator">16 - 12</gadget>
<output>4</output>

<gadget id="calculator">20 / 4</gadget>
<output>5</output>

<gadget id="calculator">5 * 12</gadget>
<output>60</output>

<gadget id="calculator">108 - 60</gadget>
<output>48</output>

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

<gadget id="calculator">4 * 6</gadget>
<output>24</output>

<gadget id="calculator">30 - 24</gadget>
<output>6</output>

<gadget id="calculator">48 + 6</gadget>
<output>54</output>

<gadget id="calculator">54 + 30</gadget>
<output>84</output>

<gadget id="calculator">84 / 6</gadget>
<output>14</output>

<gadget id="calculator">14 - 4</gadget>
<output>10</output>

<result>10</result>