Hope Primary School has 113 students in the first grade and 187 students in the second grade. Students in these two grades need to be injected with 2 shots of vaccine each. How many disposable syringes are needed in total?
希望小学一年级有113人，二年级有187人．这两个年级的学生每人要注射2针疫苗，共需要多少个一次性注射器？
<gadget id="calculator">113 + 187</gadget>
<output>300</output>

<gadget id="calculator">300 * 2</gadget>
<output>600</output>

<result>600</result>