There are 6 different math books on the upper shelf, and 5 different Chinese books on the lower shelf. One math book and one Chinese book are taken from them. There are many different ways to take it.
书架上层放着6本不同的数学书，下层放有5本不同的语文书，从中任取数学书与语文书各一本．有种多少不同的取法．
<gadget id="calculator">6 * 5</gadget>
<output>30</output>

<result>30</result>