The school cafeteria bought a batch of rice. The first time I ate half of it, more than 2 kilograms. The second time I ate the remaining half. At this time, there are still 20 kilograms. How many kilograms of this batch of rice are there?
学校食堂买了一批大米，第一次吃了全部的一半多2千克，第二次吃了余下的一半，这时还剩20千克，这批大米共有多少千克．
<gadget id="calculator">20 * 2</gadget>
<output>40</output>

<gadget id="calculator">40 + 2</gadget>
<output>42</output>

<gadget id="calculator">42 * 2</gadget>
<output>84</output>

<result>84</result>