题目内容
(2008?丰县)计算下面各题,能用简便算法的用简便算法.
1740-1632÷16×17
0.36×73-63×0.36
×
+
÷3
[(
-
)÷
]×
.
1740-1632÷16×17
0.36×73-63×0.36
9 |
10 |
5 |
3 |
9 |
10 |
[(
3 |
5 |
1 |
3 |
4 |
5 |
7 |
8 |
分析:(1)先算除法,再算乘法,最后算减法;
(2)运用乘法分配律简算;
(3)先把除法变成乘法,再运用乘法分配律简算;
(4)先把中括号里面的除法变成乘法,再运用乘法分配律简算.
(2)运用乘法分配律简算;
(3)先把除法变成乘法,再运用乘法分配律简算;
(4)先把中括号里面的除法变成乘法,再运用乘法分配律简算.
解答:解:(1)1740-1632÷16×17,
=1740-102×17,
=1740-1734,
=6;
(2)0.36×73-63×0.36,
=(73-63)×0.36,
=10×0.36,
=3.6;
(3)
×
+
÷3,
=
×
+
×
,
=
×(
+
),
=
×2,
=
;
(4)[(
-
)÷
]×
,
=[(
-
)×
]×
,
=[
×
-
×
]×
,
=[
-
]×
,
=
×
,
=
.
=1740-102×17,
=1740-1734,
=6;
(2)0.36×73-63×0.36,
=(73-63)×0.36,
=10×0.36,
=3.6;
(3)
9 |
10 |
5 |
3 |
9 |
10 |
=
9 |
10 |
5 |
3 |
9 |
10 |
1 |
3 |
=
9 |
10 |
5 |
3 |
1 |
3 |
=
9 |
10 |
=
9 |
5 |
(4)[(
3 |
5 |
1 |
3 |
4 |
5 |
7 |
8 |
=[(
3 |
5 |
1 |
3 |
5 |
4 |
7 |
8 |
=[
3 |
5 |
5 |
4 |
1 |
3 |
5 |
4 |
7 |
8 |
=[
3 |
4 |
5 |
12 |
7 |
8 |
=
1 |
3 |
7 |
8 |
=
7 |
24 |
点评:乘法分配律是最常用的简便运算的方法,要熟练掌握,灵活运用.
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