题目内容
用简便方法计算,要写出必要的计算过程
7.32-(3.8+1.32)
0.6×24+
×76
×
÷(
+
)
[7+(3-1
)]×
+3
.
7.32-(3.8+1.32)
0.6×24+
3 |
5 |
1 |
3 |
2 |
5 |
1 |
4 |
1 |
6 |
[7+(3-1
1 |
3 |
1 |
2 |
1 |
4 |
分析:(1)去括号,运用加法交换律与结合律简算;
(2)把分数化为小数,运用乘法分配律简算;
(3)先算
×
和括号内的,再算括号外的除法;
(4)先算小括号内的,再算中括号内的,然后算括号外的乘法,最后算加法.
(2)把分数化为小数,运用乘法分配律简算;
(3)先算
1 |
3 |
2 |
5 |
(4)先算小括号内的,再算中括号内的,然后算括号外的乘法,最后算加法.
解答:解:(1)7.32-(3.8+1.32),
=7.32-3.8-1.32,
=(7.32-1.32)-3.8,
=6-3.8,
=2.2;
(2)0.6×24+
×76,
=0.6×24+0.6×76,
=(24+76)×0.6,
=100×0.6,
=60;
(3)
×
÷(
+
),
=
÷
,
=
×
,
=
;
(4)[7+(3-1
)]×
+3
,
=[7+
]×
+3
,
=
×
+3
,
=4
+3
,
=(4+3)+(
+
),
=7+
,
=7
.
=7.32-3.8-1.32,
=(7.32-1.32)-3.8,
=6-3.8,
=2.2;
(2)0.6×24+
3 |
5 |
=0.6×24+0.6×76,
=(24+76)×0.6,
=100×0.6,
=60;
(3)
1 |
3 |
2 |
5 |
1 |
4 |
1 |
6 |
=
2 |
15 |
5 |
12 |
=
2 |
15 |
12 |
5 |
=
8 |
25 |
(4)[7+(3-1
1 |
3 |
1 |
2 |
1 |
4 |
=[7+
5 |
3 |
1 |
2 |
1 |
4 |
=
26 |
3 |
1 |
2 |
1 |
4 |
=4
1 |
3 |
1 |
4 |
=(4+3)+(
1 |
3 |
1 |
4 |
=7+
7 |
12 |
=7
7 |
12 |
点评:此题是考查四则混合运算,要仔细观察算式的特点,灵活运用一些定律进行简便计算.
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