Xiaoming's phone bill in January this year was 83.5 yuan, and he will save 6.8 yuan every month from the previous month. So how much will his family pay for the phone bill in April this year?
小明家今年一月份电话费83.5元，以后每个月都比上个月节约6.8元．那么他家今年四月份应付电话费多少元？
<gadget id="calculator">6.8 * 3</gadget>
<output>20.4</output>

<gadget id="calculator">83.5 - 20.4</gadget>
<output>63.1</output>

<result>63.1</result>