It is known that the walking speed ratio of Xiaoming and Xiaoqiang is 2:3, and the walking speed ratio of Xiaoqiang and Xiaogang is 4:3. It is known that Xiao Gang walked 420 meters more than Xiao Ming in 10 minutes, so how much less did Xiao Ming walk than Xiao Qiang in 20 minutes.
已知小明和小强步行的速度比是2：3，小强与小刚步行的速度比是4：3．已知小刚10分钟比小明多走420米，那么，小明在20分钟里比小强少走多少．
<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">(3/4) - (2/3)</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">420 / (1/12)</gadget>
<output>5_040</output>

<gadget id="calculator">1 - (2/3)</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">20 / 10</gadget>
<output>2</output>

<gadget id="calculator">(1/3) * 2</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">5_040 * (2/3)</gadget>
<output>3_360</output>

<result>3_360</result>