Teacher Zhang has two 50-cent and 80-cent stamps. How much postage can he pay with these stamps (the amount of money that needs to be paid when sending a letter).
张老师有50分和80分的邮票各两枚．他用这些邮票能付多少种邮资(寄信时需要付的钱数)．
<gadget id="calculator">6 + 2</gadget>
<output>8</output>

<result>8</result>