The two sides of a triangle are 7 cm and 8 cm respectively, and the third side must be shorter than how many centimeters.
一个三角形的两条边长分别是7厘米，8厘米，第三边一定比多少厘米短．
<gadget id="calculator">8 + 7</gadget>
<output>15</output>

<result>15</result>