The ratio of desktop computers to laptop computers purchased by Baijia Computer is 9:5. It is known that there are 135 desktop computers. How many more desktop computers than laptop computers are purchased by Baijia Computer City?
百佳电脑购进的台式电脑与手提电脑数量比是9：5，已知台式电脑有135台，百佳电脑城购进的台式电脑比手提电脑多多少台？
<gadget id="calculator">135 / 9</gadget>
<output>15</output>

<gadget id="calculator">9 - 5</gadget>
<output>4</output>

<gadget id="calculator">15 * 4</gadget>
<output>60</output>

<result>60</result>