Kobayashi wants to install a batch of computers, 15 computers per day for the first 6 days, and 20 computers per day for the next 7 days. How many computers are there in total?
小林要安装一批电脑，前6天每天安装15台，后7天每天安装20台．这批电脑一共有多少台？
<gadget id="calculator">15 * 6</gadget>
<output>90</output>

<gadget id="calculator">20 * 7</gadget>
<output>140</output>

<gadget id="calculator">90 + 140</gadget>
<output>230</output>

<result>230</result>