There are 3 red balls, 4 blue balls and 2 white balls in a bag, what is the probability of getting the blue balls?
袋子里有3个红球、4个蓝球和2个白球，取到蓝球的可能性大小是多少．
<gadget id="calculator">3 + 4 + 2</gadget>
<output>9</output>

<gadget id="calculator">4 / 9</gadget>
<output>4/9 = around 0.444444</output>

<result>4/9 = around 0.444444</result>