The fourth grade collected 15.3 kg of tree species, 3.25 kg more than the third grade. How many kilograms of tree species did the two grades collect in total?
四年级采集树种15.3千克，比三年级多采集了3.25千克．两个年级一共采集树种多少千克？
<gadget id="calculator">15.3 - 3.25</gadget>
<output>12.05</output>

<gadget id="calculator">12.05 + 15.3</gadget>
<output>27.35</output>

<result>27.35</result>