On a bridge, there are 10 billboards on one side, each billboard is 4 meters long and 3 meters high, and the distance between two billboards is 10 meters. The first and last billboards are 50 meters away from the end of the bridge. How long is the bridge in meters?
在一座大桥上，一侧有10块宣传牌，每块宣传牌长4米，高3米，两块宣传牌之间相距10米．第一块和最后一块宣传牌离桥端都有50米．这座大桥长多少米？
<gadget id="calculator">10 - 1</gadget>
<output>9</output>

<gadget id="calculator">10 * 9</gadget>
<output>90</output>

<gadget id="calculator">4 * 10</gadget>
<output>40</output>

<gadget id="calculator">50 * 2</gadget>
<output>100</output>

<gadget id="calculator">90 + 40 + 100</gadget>
<output>230</output>

<result>230</result>