The teacher asked Xiao Ming to choose two different types of paintings from 5 Chinese paintings, 3 oil paintings and 2 watercolor paintings to decorate the classroom. How many choices does Xiao Ming have?
老师让小明从5幅国画，3副油画和2副水彩画中选取两幅不同类型的画布置教室，则小明一共有多少种选法．
<gadget id="calculator">5 * 3</gadget>
<output>15</output>

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

<gadget id="calculator">3 * 2</gadget>
<output>6</output>

<gadget id="calculator">15 + 10 + 6</gadget>
<output>31</output>

<result>31</result>