There are 8 banknotes of 20 yuan with consecutive numbers, how many different ways are there to take out 2 banknotes with consecutive numbers?
有8张连号的20元纸币，要从中拿出2张连号的纸币，一共有多少种不同的拿法？
<gadget id="calculator">8 - 2</gadget>
<output>6</output>

<gadget id="calculator">6 + 1</gadget>
<output>7</output>

<result>7</result>