Students repair books. The fifth grade was divided into 4 groups, and a total of 28 books were repaired; the fourth grade was divided into 6 groups, and each group repaired 8 books. How many copies have been repaired in two grades?
同学们修补图书．五年级分4个组，一共修补了28本；四年级分6个组，每组修补8本．两个年级一共修补了多少本．
<gadget id="calculator">8 * 6</gadget>
<output>48</output>

<gadget id="calculator">28 + 48</gadget>
<output>76</output>

<result>76</result>