The price of 1 cup of fresh milk is 1.80 yuan, and the merchant promotes: buy 1 cup of fresh milk and get 1 lottery coupon, 3 lottery coupons can be exchanged for 1 cup of fresh milk, and the value of each lottery coupon is equivalent to how many yuan.
1杯鲜奶售价1.80元，商家促销：买1杯鲜奶送奖券1张，3张奖券兑换1杯鲜奶，每张奖券的价值相当于多少元．
<gadget id="calculator">3 + 1</gadget>
<output>4</output>

<gadget id="calculator">1.8 / 4</gadget>
<output>0.45</output>

<result>0.45</result>