The experimental primary school needs to buy a composition guidance book for each student in the third grade at a price of 12 yuan, and a children's book for each student in the fourth grade. There are 145 students in the third grade, 155 students in the fourth grade, and 155 students in the two grades. How much is the total cost for each grade?
实验小学要为三年级的学生每人买一本价格为12元的作文辅导书，四年级每人买一本价格为18元的儿童读物知三年级有145人，四年级有155人，两个年级一共需要多少元？
<gadget id="calculator">12 * 145</gadget>
<output>1_740</output>

<gadget id="calculator">18 * 155</gadget>
<output>2_790</output>

<gadget id="calculator">1_740 + 2_790</gadget>
<output>4_530</output>

<result>4_530</result>