If the length, width, and height of a cuboid are 5 decimeters, 4 decimeters, and 3 decimeters, what is the sum of the areas of the front and top surfaces of the cuboid?
一个长方体的长、宽、高分别为5分米、4分米、3分米，那么这个长方体前面和上面两个面的面积之和是多少平方分米．
<gadget id="calculator">5 * 3</gadget>
<output>15</output>

<gadget id="calculator">5 * 4</gadget>
<output>20</output>

<gadget id="calculator">15 + 20</gadget>
<output>35</output>

<result>35</result>