The fourth and fifth grades collected tree species, the fifth grade collected 19.4 kg, and the fifth grade collected 3.5 kg more than the fourth grade. How many kilograms of tree species did the two grades collect in total?
四、五年级采集树种，五年级采集了19.4千克，五年级采集的比四年级多3.5千克．两个年级一共采集树种多少千克？
<gadget id="calculator">19.4 - 3.5</gadget>
<output>15.9</output>

<gadget id="calculator">15.9 + 19.4</gadget>
<output>35.3</output>

<result>35.3</result>