Mother's mobile phone has 600 yuan in calls. If she spends 57.5 yuan a month on average and uses it for one and a half years, how much is the difference?
妈妈手机有600元的话费，如果平均每个月用掉57.5元，使用1年半，还差多少？
<gadget id="calculator">18 * 57.5</gadget>
<output>1_035</output>

<gadget id="calculator">1_035 - 600</gadget>
<output>435</output>

<result>435</result>