4/5+(7/8−4/5) 7/10−(2/15+1/6) 1−1/3−1/7.
问题描述:
+(4 5
−7 8
)4 5
−(7 10
+2 15
)1 6
1−
−1 3
. 1 7
答
(1)
+(4 5
-7 8
),4 5
=
+4 5
-7 8
,4 5
=
-4 5
+4 5
,7 8
=
;7 8
(2)
-(7 10
+2 15
),1 6
=
-7 10
,3 10
=
;2 5
(3)1-
-1 3
,1 7
=1-
-7 21
,3 21
=
.11 21