Mom bought a pack of 2000 grams of miscellaneous grains, of which (1/7) is oatmeal, (2/5) is black rice, and the rest are ordinary rice. What percentage of the miscellaneous grains does rice account for?
妈妈买了一包2000克的杂粮，其中(1/7)是燕麦仁，(2/5)是黑米，其余的都是普通大米，大米占这份杂粮的几分之几？
<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (1/7) - (2/5)</gadget>
<output>16/35 = around 0.457143</output>

<result>16/35 = around 0.457143</result>