cuboid gift box, 10 cm long, 7 cm wide, and 3 cm high. How many square centimeters of hard paper does a gift box need?
一种长方体礼品盒，长10厘米，宽7厘米，高3厘米．做怎样一个礼品盒需要多少平方厘米的硬纸？
<gadget id="calculator">10 * 7</gadget>
<output>70</output>

<gadget id="calculator">10 * 3</gadget>
<output>30</output>

<gadget id="calculator">7 * 3</gadget>
<output>21</output>

<gadget id="calculator">70 + 30 + 21</gadget>
<output>121</output>

<gadget id="calculator">121 * 2</gadget>
<output>242</output>

<result>242</result>