5⼀21*2⼀7+61⼀21*5⼀7+(1-2⼀7)怎么简便计算

2025-04-26 02:10:50
推荐回答(1个)
回答1:

5/21*(1-5/7)+61/21*5/7+5/7
=5/21-5/21*5/7+61/21*5/7+5/7
=5/21+5/7(-5/21+61/21+21/21)
=5/21+5/7*77/21
=60/21