题目内容
(2013?吴中区模拟)用你喜欢的方法计算.
(
|
3.3×
| ||||||||||||||
|
1-[1-(
|
分析:(1)先把12×17结合在一起,然后运用乘法分配律简算;
(2)先把除法变成乘法,再运用乘法分配律简算;
(3)运用乘法分配律简算;
(4)先算小括号里面的除法,再算小括号里面的减法,然后算中括号里面的减法,接着算括号外的乘法,最后算括号外的减法.
(2)先把除法变成乘法,再运用乘法分配律简算;
(3)运用乘法分配律简算;
(4)先算小括号里面的除法,再算小括号里面的减法,然后算中括号里面的减法,接着算括号外的乘法,最后算括号外的减法.
解答:解:(1)(
-
)×12×17,
=(
-
)×(12×17),
=(
×12×17)-(
×17×12),
=(1×17)-(
×12),
=17-4,
=13;
(2)3.3×
+8×
+2.7÷1
,
=3.3×
+8×
+2.7×
,
=(3.3+8+2.7)×
,
=14×
,
=8;
(3)
×0.8+
+
×80%,
=(
+1+
)×0.8,
=2×0.8,
=1.6;
(4)1-[1-(
-
÷
)]×
,
=1-[1-(
-
)]×
,
=1-[1-
]×
,
=1-
×
,
=1-
,
=
.
| 1 |
| 12 |
| 1 |
| 51 |
=(
| 1 |
| 12 |
| 1 |
| 51 |
=(
| 1 |
| 12 |
| 1 |
| 51 |
=(1×17)-(
| 1 |
| 3 |
=17-4,
=13;
(2)3.3×
| 4 |
| 7 |
| 4 |
| 7 |
| 3 |
| 4 |
=3.3×
| 4 |
| 7 |
| 4 |
| 7 |
| 4 |
| 7 |
=(3.3+8+2.7)×
| 4 |
| 7 |
=14×
| 4 |
| 7 |
=8;
(3)
| 8 |
| 17 |
| 4 |
| 5 |
| 9 |
| 17 |
=(
| 8 |
| 17 |
| 9 |
| 17 |
=2×0.8,
=1.6;
(4)1-[1-(
| 3 |
| 4 |
| 3 |
| 4 |
| 6 |
| 5 |
| 7 |
| 8 |
=1-[1-(
| 3 |
| 4 |
| 5 |
| 8 |
| 7 |
| 8 |
=1-[1-
| 1 |
| 8 |
| 7 |
| 8 |
=1-
| 7 |
| 8 |
| 7 |
| 8 |
=1-
| 49 |
| 64 |
=
| 15 |
| 64 |
点评:本题考查了四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律进行简便计算.
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