There are two classes in the fourth grade of Guangming Primary School, with 52 students in the first class of the fourth grade and 48 students in the second class of the fourth grade. 13 homework books are distributed to each student at the beginning of the term. How many homework books should be distributed in the fourth grade? (first step by step and then synthesis)
光明小学四年级有两个班，四年级一班52人，四年级二班48人．开学时每人发13个作业本，四年级一共要发多少个作业本？(先分步再综合)
<gadget id="calculator">52 + 48</gadget>
<output>100</output>

<gadget id="calculator">100 * 13</gadget>
<output>1_300</output>

<result>1_300</result>