There are five colors of flowers, red, white, yellow, blue, and black, and two of the colors are placed in a vase. How many different ways are there in total?
有红、白、黄、蓝、黑5种颜色的花，将其中两种花色插一瓶，共有多少种不同的插法．
<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">5 / 2</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">4 * (5/2)</gadget>
<output>10</output>

<result>10</result>