A pocket with colored balls, red balls accounted for the total number (5/14), and later put 21 red balls, at this time the red balls accounted for the current total (4/7), ask the original total number of colored balls in the pocket How many balls are there?
一个装有彩球的口袋，红球占总数量的(5/14)，后来又放进21个红球，这时红球占现在总量的(4/7)，问口袋里原来共有彩球多少个？
<gadget id="calculator">4 / 7</gadget>
<output>4/7 = around 0.571429</output>

<gadget id="calculator">(4/7) * 21</gadget>
<output>12</output>

<gadget id="calculator">21 - 12</gadget>
<output>9</output>

<gadget id="calculator">5 / 14</gadget>
<output>5/14 = around 0.357143</output>

<gadget id="calculator">(4/7) - (5/14)</gadget>
<output>3/14 = around 0.214286</output>

<gadget id="calculator">9 / (3/14)</gadget>
<output>42</output>

<result>42</result>