10 table tennis balls of the same model, 7 of the first-class product, 2 of the second-class product, and 1 of the third-class product, choose any one from them, what is the possibility of not getting the third-class product?
10个型号相同的乒乓球，一等品7个，二等品2个，三等品1个，从中任意取一个，没取到三等品的可能性是多少．
<gadget id="calculator">7 + 2</gadget>
<output>9</output>

<gadget id="calculator">9 / 10</gadget>
<output>9/10 = around 0.9</output>

<result>9/10 = around 0.9</result>