30% of the total length of a 4,200-meter road has been repaired, how many meters are left to be repaired?
修一段4200米的路，已修全长的30%，还有多少米没有修？
<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">4_200 * (3/10)</gadget>
<output>1_260</output>

<gadget id="calculator">4_200 - 1_260</gadget>
<output>2_940</output>

<result>2_940</result>