The fourth and fifth graders collected tree species, the fifth grade collected 19.2 kg, and the fifth grade collected 3.8 kg more than the fourth grade. How many kilograms of tree species were collected by these two grades?
四五年级的学生采集树种，五年级采集了19.2千克，五年级采集的比四年级多3.8千克，这两个年级一共采集树种多少千克？
<gadget id="calculator">19.2 - 3.8</gadget>
<output>15.4</output>

<gadget id="calculator">15.4 + 19.2</gadget>
<output>34.6</output>

<result>34.6</result>