Wang Hong, Zhang Wei, and Li Dong jointly bought 6 bags of candy and shared them equally. Wang Hong paid 3.9 yuan, Zhang Wei paid 3.3 yuan, and Li Dong did not pay. How much should Li Dong pay Zhang Wei?
王红、张伟、李东三人合买6袋千克糖平均分吃，王红付3.9元，张伟付了3.3元，李东没有付钱，李东应付给张伟多少元？
<gadget id="calculator">3.9 + 3.3</gadget>
<output>7.2</output>

<gadget id="calculator">7.2 / 3</gadget>
<output>2.4</output>

<gadget id="calculator">3.3 - 2.4</gadget>
<output>0.9</output>

<result>0.9</result>