三十一分之二一乘1.58三十一分之二一乘1.58?

2025-12-14 03:00:27
推荐回答(1个)
回答1:

21/31×1.58=21/31×79/50
=(20+1)×(80-1)/1550
=(1600+80-20-1)/1550
=1669/1550