According to the tariff standard of China Mobile, the domestic long-distance roaming call fee is about 0.6 yuan per minute. After opening "long distance worry-free" (19:00-7:00), the long-distance call fee is only the original (1/3) ． Xiaoqiang's father's monthly mobile phone bill is about 180 yuan, of which (1/3) is for long-distance calls. How much can Xiaoqiang's father save in mobile phone bills every month after opening the "Worry-free Long Call" service?
按照中国移动的资费标准，国内长途漫游通话费的标准大约是0.6元/分钟，开通"长话无忧"(19：00-7：00)后，长途通话费只有原来的(1/3)．小强的爸爸每月的手机费大约180元，其中(1/3)是长途通话费，开通"长话无忧"后，小强的爸爸每月可节约手机费多少元？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">180 * (1/3) * (2/3)</gadget>
<output>40</output>

<result>40</result>