To make a drawer with a length of 60 cm, a width of 70 cm, and a height of 12 cm, how many square centimeters of wooden boards are needed at least?
做一个抽屉，长60厘米，宽70厘米，高12厘米，至少需要木板多少平方厘米？
<gadget id="calculator">60 * 70</gadget>
<output>4_200</output>

<gadget id="calculator">60 * 12</gadget>
<output>720</output>

<gadget id="calculator">70 * 12</gadget>
<output>840</output>

<gadget id="calculator">720 + 840</gadget>
<output>1_560</output>

<gadget id="calculator">1_560 * 2</gadget>
<output>3_120</output>

<gadget id="calculator">4_200 + 3_120</gadget>
<output>7_320</output>

<result>7_320</result>