差之毫厘，谬以千里（差之毫釐，謬以千里）　

◎ 差之毫厘,谬以千里 chā zhī háolí,miù yǐ qiānlǐ

[a minimal error or deviation results in wide divergence;a small error can lead to a serious result] 亦作“差之毫厘,失之千里。”最初时小小的差错,其后果可能酿成极大错误。强调不能有丝毫差错