185 students take 4 buses to go on a picnic, the first 3 cars each take 45 students, how many students should the fourth car take?
185个同学乘4辆客车去郊游，前3辆车各坐45个同学，第四辆车要坐多少个同学？
<gadget id="calculator">45 * 3</gadget>
<output>135</output>

<gadget id="calculator">185 - 135</gadget>
<output>50</output>

<result>50</result>