Choose two numbers from the five numbers 1, 3, 5, 7, and 9, and write them on both sides of the multiplication sign to form a multiplication formula. How many formulas with different products can be obtained
从1、3、5、7、9这五个数字中任选2个，分别写在乘号的两边，组成一道乘法算式．共可得到多少个乘积不同的算式多少
<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<gadget id="calculator">5 * 2</gadget>
<output>10</output>

<result>10</result>