(3/4+2/5)*(2/3-2/9) (1/3+1/5)/(2/3+2/5) 用合适的方法计算

来源:学生作业帮助网 编辑:作业帮 时间:2024/05/12 01:31:05

(3/4+2/5)*(2/3-2/9) (1/3+1/5)/(2/3+2/5) 用合适的方法计算
(3/4+2/5)*(2/3-2/9) (1/3+1/5)/(2/3+2/5) 用合适的方法计算

(3/4+2/5)*(2/3-2/9) (1/3+1/5)/(2/3+2/5) 用合适的方法计算
(3/4+2/5)*(2/3-2/9)
=(3/4+2/5)*(6/9-2/9)
= (3/4+2/5)*(4/9)
=(3/4)(4/9)+(2/5)(4/9)
=1/3+8/45
=15/45+8/45
=23/45
(1/3+1/5)/(2/3+2/5)
=(1/3+1/5)/[2(1/3+1/5)]
=1/2