A dining table is 12 decimeters long and 7 decimeters longer than its width. How many square decimeters of glass do you need to buy to match the table top with a piece of glass of the same size?
一张餐桌长12分米，比宽长7分米，要给这张餐桌面配一块同样大小的玻璃，需要买多少平方分米的玻璃？
<gadget id="calculator">12 - 7</gadget>
<output>5</output>

<gadget id="calculator">5 * 12</gadget>
<output>60</output>

<result>60</result>