The knitting factory inspects the products and randomly checks some woolen sweaters. 1491 pieces are qualified and 9 pieces are unqualified. Find the pass rate.
针织厂检验产品，抽查了一些羊毛衫，合格的有1491件，不合格的有9件，求合格率．
<gadget id="calculator">1_491 + 9</gadget>
<output>1_500</output>

<gadget id="calculator">1_491 / 1_500</gadget>
<output>497/500 = around 0.994</output>

<gadget id="calculator">100 / 100</gadget>
<output>1</output>

<gadget id="calculator">(497/500) * 1</gadget>
<output>497/500 = around 0.994</output>

<result>497/500 = around 0.994</result>