Master Li processes a batch of parts. If he processes 54 parts per hour, it will be completed 1 hour earlier than the original time; if he processes 45 parts per hour, it will be completed 1 hour later than the original time. How many parts are there in this batch? (Solution by proportional method)
李师傅加工一批零件，如果每小时加工54个，那么将比原定时间提前1小时完成；如果每小时加工45个，那么将比原定时间延迟1小时完成，这批零件共有多少个？(用比例方法解)
<gadget id="calculator">54 + 45</gadget>
<output>99</output>

<gadget id="calculator">54 - 45</gadget>
<output>9</output>

<gadget id="calculator">99 / 9</gadget>
<output>11</output>

<gadget id="calculator">11 - 1</gadget>
<output>10</output>

<gadget id="calculator">54 * 10</gadget>
<output>540</output>

<result>540</result>