Xiao Ming went to grandma's house by car, and the speed was 70 km/h. It took 4 hours, and it took 5 hours to return. How many kilometers per hour did he travel on average when he returned?
小明坐车去姥姥家，去时的速度是70千米/时，用了4小时，返回时用了5小时，返回时平均每小时行多少千米？
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">70 * (4/5)</gadget>
<output>56</output>

<result>56</result>