Xiao Ming wants to climb 7 steps. He can only climb 1 or 2 steps at each step. How many different climbing methods can he climb 6 steps?
小明要登上7级台阶，他每一步只能登1级或2级台阶，他登上6级台阶共有多少种不同的登法．
<gadget id="calculator">1 + 2</gadget>
<output>3</output>

<gadget id="calculator">2 + 3</gadget>
<output>5</output>

<gadget id="calculator">3 + 5</gadget>
<output>8</output>

<gadget id="calculator">5 + 8</gadget>
<output>13</output>

<result>13</result>