There are apples and pears in the fruit shop. Originally, apples accounted for (5/9); now after 21 kg of pears are brought in, apples only account for (2/5). How many kilograms are the pears now?
水果店里有苹果和梨，原来苹果占(5/9)；现在又运进21千克梨后，苹果就只占(2/5)了．现在梨有多少千克？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">5 / 9</gadget>
<output>5/9 = around 0.555556</output>

<gadget id="calculator">21 * (2/5) * (5/9)</gadget>
<output>14/3 = around 4.666667</output>

<gadget id="calculator">(5/9) - (2/5)</gadget>
<output>7/45 = around 0.155556</output>

<gadget id="calculator">(14/3) / (7/45) / (2/5)</gadget>
<output>75</output>

<gadget id="calculator">(14/3) / (7/45)</gadget>
<output>30</output>

<gadget id="calculator">75 - 30</gadget>
<output>45</output>

<result>45</result>