250chain是多少m？
250chain = 5,029.2m
是5,029.2m，所以说成5,029m也没问题——四舍五入的误差在0.5%以内。
反过来，250m是多少chain？
250m = 12.4274chain
计算公式: m = chain × 20.1168
该数值前后的 chain → m
70 chain1,408.176m
90 chain1,810.512m
110 chain2,212.848m
130 chain2,615.184m
150 chain3,017.52m
170 chain3,419.856m
190 chain3,822.192m
210 chain4,224.528m
230 chain4,626.864m
250 chain5,029.2m
270 chain5,431.536m
290 chain5,833.872m
310 chain6,236.208m
330 chain6,638.544m
350 chain7,040.88m
370 chain7,443.216m
390 chain7,845.552m
410 chain8,247.888m
430 chain8,650.224m
450 chain9,052.56m