It costs 6 yuan and 80 cents to buy some 4-cent and 8-cent stamps. It is known that there are 40 more 8-cent stamps than 4-cent stamps, so how many 8-cent stamps are there?
买一些4分与8分的邮票共花6元8角，已知8分的邮票比4分的多40张，那么8分的邮票有多少张．
<gadget id="calculator">8 * 40</gadget>
<output>320</output>

<gadget id="calculator">680 - 320</gadget>
<output>360</output>

<gadget id="calculator">4 + 8</gadget>
<output>12</output>

<gadget id="calculator">360 / 12</gadget>
<output>30</output>

<gadget id="calculator">30 + 40</gadget>
<output>70</output>

<result>70</result>