Class 51 was decorating the classroom to celebrate New Year's Day. Teacher Zhang bought 40 balloons and paid 50 yuan. The recovered money happened to buy 4 ribbons with a unit price of 4.5 yuan. How much is each balloon?
五1班庆祝元旦布置教室，张老师买了40个气球，付出50元，找回的钱正好买了4根单价为4.5元的彩带，每个气球多少钱？
<gadget id="calculator">4 * 4.5</gadget>
<output>18</output>

<gadget id="calculator">50 - 18</gadget>
<output>32</output>

<gadget id="calculator">32 / 40</gadget>
<output>4/5 = around 0.8</output>

<result>4/5 = around 0.8</result>