In order to encourage saving electricity, a power company in a certain city stipulates the following calculation method of electricity charges: monthly electricity consumption does not exceed 100 kWh, charged at 0.54 yuan per kWh; monthly electricity consumption exceeds 100 kWh, the excess part is charged per The fee is 0.68 yuan per hour. Xiaoming's family pays 67.6 yuan for electricity in October, so how many kilowatt-hours does his household use?
为了鼓励节约用电，某市电力公司规定了以下的电费计算方法：每月用电不超过100千瓦时，按每千瓦时0.54元收费；每月用电超过100千瓦时，超过部分按每千瓦时0.68元收费．小明家十月份付电费67.6元，那么他家用电多少千瓦时？
<gadget id="calculator">0.54 * 100</gadget>
<output>54</output>

<gadget id="calculator">67.6 - 54</gadget>
<output>13.6</output>

<gadget id="calculator">13.6 / 0.68</gadget>
<output>20</output>

<gadget id="calculator">20 + 100</gadget>
<output>120</output>

<result>120</result>