Also walk 100 meters, Xiaoming has to walk 180 steps, and father has to walk 120 steps. Father and son start from the same place in the same direction at the same time. If the time taken for each step is the same, then how many steps does the father have to walk to meet Xiaoming after walking back after walking 450 meters?
同样走100米，小明要走180步，父亲要走120步．父子同时同方向从同一地点出发，如果每走一步所用的时间相同，那么父亲走出450米后往回走，还要走多少步才能遇到小明？
<gadget id="calculator">5 / 6</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">450 / (5/6)</gadget>
<output>540</output>

<gadget id="calculator">5 / 9</gadget>
<output>5/9 = around 0.555556</output>

<gadget id="calculator">540 * (5/9)</gadget>
<output>300</output>

<gadget id="calculator">450 - 300</gadget>
<output>150</output>

<gadget id="calculator">(5/6) + (5/9)</gadget>
<output>25/18 = around 1.388889</output>

<gadget id="calculator">150 / (25/18)</gadget>
<output>108</output>

<result>108</result>