When New Year's Day came, 40 students from Class 1 of the fourth grade sent greeting cards to the students in the earthquake-stricken areas to express their condolences and congratulate the New Year. Each of them made an average of 15 greeting cards. If each stamp is 1 yuan and 2 cents, each envelope is 2 cents. So how much does it cost to send these greeting cards?
元旦节到了，四年级一班40个同学给地震灾区的同学们送贺卡表示慰问，祝贺新年．他们每人平均做了15张贺卡，如果每张邮票1元2角，每个信封2角．那么寄出这些贺卡一共需要花多少钱？
<gadget id="calculator">2 / 10</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 + (1/5)</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">(6/5) + 0.2</gadget>
<output>1.4</output>

<gadget id="calculator">40 * 15 * 1.4</gadget>
<output>840</output>

<result>840</result>