There are still 45 skipping ropes in the school sports room after half of them are lent out. Learn how many skipping ropes there are in the gym.
学校体育室里的跳绳借出一半后还有45根．学较体育室里原有多少根跳绳．
<gadget id="calculator">45 * 2</gadget>
<output>90</output>

<result>90</result>