There are 4 yellow balls, 3 red balls, 2 green balls and 1 blue ball in a pocket. If a ball is randomly drawn from the pocket, what is the probability of getting a green ball?
口袋里有4个黄球，3个红球，2个绿球和1个蓝球，从口袋里任意摸出一个球，摸到绿球的可能性是多少．
<gadget id="calculator">4 + 3 + 2 + 1</gadget>
<output>10</output>

<gadget id="calculator">2 / 10</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>