In order to encourage residents to save electricity, a county electric power company calculates the electricity bill by monthly segment, 0.6 yuan per kWh within 20 kWh, and 1.2 yuan per kWh for the part exceeding 20 kWh. Liu Jun’s home used 45 kwh of electricity last month, how much kwh should I pay for electricity?
为了鼓励居民节约用电，某县电力公司采取按月分段计算电费，20度以内每度0.6元，超过20度的部分，每度1.2元．刘军家上个月用电为45度，应缴电费多少度？
<gadget id="calculator">20 * 0.6</gadget>
<output>12</output>

<gadget id="calculator">45 - 20</gadget>
<output>25</output>

<gadget id="calculator">25 * 1.2</gadget>
<output>30</output>

<gadget id="calculator">12 + 30</gadget>
<output>42</output>

<result>42</result>