The fourth-grade students planted 84 sunflowers, with an average of 0.4 kg of sunflower seeds per tree; the third-grade students planted 65 sunflowers, with an average of 0.42 kg of sunflower seeds per tree. Which grade produces the most sunflowers? How many kilograms more?
四年级学生种了84棵向日葵，平均每棵收葵花籽0.4千克；三年级学生种了65棵向日葵，平均每棵收葵花籽0.42千克．哪个年级种的向日葵的产量多？多多少千克？
<gadget id="calculator">0.4 * 84</gadget>
<output>33.6</output>

<gadget id="calculator">0.42 * 65</gadget>
<output>27.3</output>

<gadget id="calculator">33.6 - 27.3</gadget>
<output>6.3</output>

<result>6.3</result>