small-displacement car consumes 7 liters of fuel per 100 kilometers of driving, and another large-scale car consumes 9 liters of fuel per 100 kilometers of driving. For the same journey of 50 kilometers, how many liters of fuel can a small-displacement car save compared to a large-displacement car?
一款小排量轿车每行驶100千米消耗燃油7升，另一款大牌量轿车每行驶100千米消耗燃油9升．同样是行驶50千米的路程，小排量轿车比大排量轿车节省燃油多少升？
<gadget id="calculator">9 / 100</gadget>
<output>9/100 = around 0.09</output>

<gadget id="calculator">(9/100) * 50</gadget>
<output>9/2 = around 4.5</output>

<gadget id="calculator">7 / 100</gadget>
<output>7/100 = around 0.07</output>

<gadget id="calculator">(7/100) * 50</gadget>
<output>7/2 = around 3.5</output>

<gadget id="calculator">(9/2) - (7/2)</gadget>
<output>1</output>

<result>1</result>