Xiao Ming bought 3 thermos bottles for 150 yuan, and the waiter returned 21 yuan. How much is each thermos bottle?
小明用150元钱买了3个热水瓶，服务员找回21元钱，每个热水瓶多少元钱？
<gadget id="calculator">150 - 21</gadget>
<output>129</output>

<gadget id="calculator">129 / 3</gadget>
<output>43</output>

<result>43</result>