Xiao Ming and grandma climb the stairs, and Xiao Ming's speed is three times that of grandma. When grandma reaches the 4th floor, how many floors has Xiao Ming reached?
小明与奶奶爬楼梯，小明的速度是奶奶的3倍．当奶奶到4楼时，小明已经到达多少楼．
<gadget id="calculator">4 - 1</gadget>
<output>3</output>

<gadget id="calculator">3 * 3</gadget>
<output>9</output>

<gadget id="calculator">9 + 1</gadget>
<output>10</output>

<result>10</result>