In order to beautify the city, Guangming Primary School held tree species collection activities. The first class of the fifth grade collected (4/5) kilograms, the second class of the fifth grade collected (3/4) kilograms, and the third class of the fifth grade collected more than the first and second classes. The total number is less (1/2) kg. How many kilograms of tree species did the third class of the fifth grade collect?
为美化城市，光明小学举行采集树种活动，五年级一班采集了(4/5)千克，五年级二班采集了(3/4)千克，五年级三班采集的比一班、二班采集的总数少(1/2)千克．五年级三班采集树种多少千克？
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(3/4) - (1/2)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(4/5) + (1/4)</gadget>
<output>21/20 = around 1.05</output>

<result>21/20 = around 1.05</result>