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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