Xiao Ming has 7 red balls and 6 white balls. What is the number of white balls in the total number of balls?
小明有7个红球，6个白球，白球的个数占全部球个数的多少
<gadget id="calculator">6 + 7</gadget>
<output>13</output>

<gadget id="calculator">6 / 13</gadget>
<output>6/13 = around 0.461538</output>

<result>6/13 = around 0.461538</result>