Master Li and Master Wang worked together to process a batch of parts, and it took 4 hours to complete the task. Master Wang processes 40 parts per hour, and Master Li processes 45 parts per hour. How many parts are there in total?
李师傅和王师傅共同加工一批零件、加工了4小时才完成任务．王师傅每小时加工40个，李师傅每小时加工45个，这批零件一共有多少个？
<gadget id="calculator">40 + 45</gadget>
<output>85</output>

<gadget id="calculator">85 * 4</gadget>
<output>340</output>

<result>340</result>