75×21+25×37用简便算法怎末算_数学解答

75×21+25×37用简便算法怎末算

人气：412 ℃　时间：2020-03-21 10:19:36

解答

75×21+25×37
=(100-25)×21+25×37
=100×21+25×21+25×37
=100×21+(37-21)×25
=2100+16×25
=2100+4×4×25
=2100+4×100
=2100+400
=2500