计算(能简便的必须简算) 91×1/17+9÷17−1÷17×100 0.38×7−19/50+4×19/50 2100÷[56×(3/7−3/8)] [(2/3−1/4)÷5/6+1/2]×3/4.
问题描述:
计算(能简便的必须简算)
91×
|
0.38×7−
|
||||||||||||||
2100÷[56×(
|
[(
|
答
(1)91×
+9÷17−1÷17×100,1 17
=91×
+9×1 17
-1 17
×100,1 17
=(91+9-100)×
,1 17
=0×
,1 17
=0;
(2)0.38×7−
+4×19 50
,19 50
=0.38×7-0.38+4×0.38,
=0.38×(7-1+4),
=0.38×10,
=3.8;
(3)2100÷[56×(
−3 7
)],3 8
=2100÷[56×
-56×3 7
],3 8
=2100÷[24-21],
=2100÷3,
=700;
(4)[(
−2 3
)÷1 4
+5 6
]×1 2
,3 4
=[
÷5 12
+5 6
]×1 2
,3 4
=[
×5 12
+6 5
]×1 2
,3 4
=[
+1 2
]×1 2
,3 4
=1×
,3 4
=
.3 4