Xiaogang left home at 8:10 in the morning to attend the rehearsal of a cultural program at school. He walked at a speed of 50 meters per minute and was expected to arrive at school 10 minutes earlier. Running home at speed, it took 2 minutes to find the music score; then walked at a speed of 70 meters per minute, and arrived at school 1 minute earlier. Find the distance from Xiaogang's home to the school.
小刚早晨8时10分离家到学校参加文艺节目排练，以每分钟50米的速度步行，预计能提前10分钟到校，刚走出500米，发现忘了带乐谱，便以每分钟100米的速度跑回家，找乐谱花了2分钟；便以每分钟70米的速度行走，结果提前1分钟到校．求小刚家到学校的距离．
<gadget id="calculator">500 / 50</gadget>
<output>10</output>

<gadget id="calculator">500 / 100</gadget>
<output>5</output>

<gadget id="calculator">2 - 9</gadget>
<output>-7</output>

<gadget id="calculator">10 + 5 + (-7)</gadget>
<output>8</output>

<gadget id="calculator">1 / 50</gadget>
<output>1/50 = around 0.02</output>

<gadget id="calculator">1 / 70</gadget>
<output>1/70 = around 0.014286</output>

<gadget id="calculator">(1/50) - (1/70)</gadget>
<output>1/175 = around 0.005714</output>

<gadget id="calculator">8 / (1/175)</gadget>
<output>1_400</output>

<result>1_400</result>