Xiao Ming bought 15 stamps of 0.60 yuan and 0.80 yuan each. How much should he pay in total?
小明买了0.60元和0.80元的邮票各15枚，一共要付多少钱？
<gadget id="calculator">0.6 + 0.8</gadget>
<output>1.4</output>

<gadget id="calculator">1.4 * 15</gadget>
<output>21</output>

<result>21</result>