The two sides of a triangle are 4 decimeters and 5 decimeters respectively, and the third side must be shorter than how many decimeters.
一个三角形的两条边长分别是4分米、5分米，第三条边一定比多少分米短．
<gadget id="calculator">5 + 4</gadget>
<output>9</output>

<result>9</result>