After cutting a cuboid steel with a length of 7 decimeters into two parts, the surface area increases by 10 decimeters, what is the volume of the original cuboid?
把一块长7分米的长方体钢材截成两段后，表面积增加了10平方分米，原来长方体的体积是多少立方分米？
<gadget id="calculator">10 / 2</gadget>
<output>5</output>

<gadget id="calculator">5 * 7</gadget>
<output>35</output>

<result>35</result>