怎样简便怎样算42×25加58×15?

2025-06-26 19:15:31
推荐回答(1个)
回答1:

42×25
=2×21×25
=(2×25)×21
=50×21
=50×(20+1)
=50×20+50
=1000+50
=1050

58×15
=58×5×3
=870

870+1050=1920
=(2×25)×21
=50×21
=50×(20+1)
=50×20+50
=1000+50
=1050