3rd and 4th grade collect tree species. The fourth grade collected a total of 24.08 kilograms, which was 3.4 kilograms more than the third grade. How many kilograms were collected by the two grades? ?
三、四年级采集树种．四年级采集了共24.08千克，比三年级多采了3.4千克，两个年级共采集了多少千克？？
<gadget id="calculator">24.08 - 3.4</gadget>
<output>20.68</output>

<gadget id="calculator">20.68 + 24.08</gadget>
<output>44.76</output>

<result>44.76</result>