The school plans to buy 20 volleyballs, which cost 360 yuan based on the market price; now it is decided to buy 15 more, so how much is the total cost?
学校计划买20个排球，按商场价计算要用360元；现决定多买15个，那么一共需用多少元．
<gadget id="calculator">360 / 20</gadget>
<output>18</output>

<gadget id="calculator">20 + 15</gadget>
<output>35</output>

<gadget id="calculator">18 * 35</gadget>
<output>630</output>

<result>630</result>