题目

150-120除以1.4×0.84 简算
17又2/5×37-174×1.9+17又2/5×82 简算
1999又1991/1999×1/4-1997/1999 简算

提问时间：2020-11-23

答案

(150-120)/1.4x0.84
=150/1.4x0.84-120/1.4x0.84
=25/1.4x0.14-20/1.4x0.14
=(25-20)/1.4x0.14
=5/0.196
=500/196
=125/49
17又2/5×37-174×1.9+17又2/5×82
=87/5x37-174x19/10+17又2/5×82
=87/5(37-19+82)
=87/5x100
=184
1999又1991/1999×1/4-1997/1999
=｛［(2000-1)²+(2000-9)］/(2000-1)｝1/4-（2000-3)/(2000-1)
=［(4000000-4000+1+2000-9)/(2000-1)］1/4-（2000-3)/(2000-1)
=(1000000-1000+500-2-2000+3)/(2000-1)
=997501/1999
=499