Now there are 7 colors, and every time two different colors are taken, a new color can be made. How many new colors can be made in total?
现在有7种颜色，每取两种不同的颜色就可以配出一种新颜色，一共能配出多少种新颜色？
<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<gadget id="calculator">7 * 3</gadget>
<output>21</output>

<result>21</result>