Mom brought 800 yuan, 450 yuan was used to buy a mobile phone, and 185 yuan was used to buy books. How much money is left?
妈妈带了800元钱，买手机用去450元，买书用去了185元，还剩多少元？
<gadget id="calculator">800 - 450 - 185</gadget>
<output>165</output>

<result>165</result>