Xiao Ming and grandma went upstairs at the same time. When grandma went up to the third floor, Xiao Ming went up to the fifth floor. So when Xiao Ming went up to the 7th floor, how many floors did grandma go up to?
小明和奶奶同时上楼，当奶奶上到了3楼的时候，小明上到5楼．那么当小明上到7楼的时候，奶奶上到多少楼．
<gadget id="calculator">7 - 1</gadget>
<output>6</output>

<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<gadget id="calculator">3 + 1</gadget>
<output>4</output>

<result>4</result>