Tianyuan Primary School has to buy a composition guidance book for each of the fourth and fifth grade students at a price of 16 yuan. It is known that there are 155 students in the fourth grade and 145 students in the fifth grade. How much is the total cost for the two grades?
天元小学要为四、五年级的学生每人买一本价格为16元的作文辅导书．已知四年级有155人，五年级有145人，两个年级一共需要多少元？
<gadget id="calculator">155 + 145</gadget>
<output>300</output>

<gadget id="calculator">16 * 300</gadget>
<output>4_800</output>

<result>4_800</result>