Xiao Ming goes upstairs twice as fast as grandpa. When grandpa goes up to the third floor, how many floors does Xiao Ming go up to?
小明上楼的速度是爷爷的2倍，当爷爷上到3楼时，小明上到多少楼．
<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<gadget id="calculator">4 + 1</gadget>
<output>5</output>

<result>5</result>