Put 7 red pencils and 3 blue pencils in a bag, let you take out one at a time, do this 20 times, how much of the total number of times you get red pencils.
把7支红铅笔和3支蓝铅笔放在一个包里，让你每次往里摸出1支，这样摸20次，摸出红铅笔大约占总次数的多少．
<gadget id="calculator">3 + 7</gadget>
<output>10</output>

<gadget id="calculator">7 / 10</gadget>
<output>7/10 = around 0.7</output>

<result>7/10 = around 0.7</result>