题目内容
脱式计算、能简算的要简算:
|
| ||||||||||||||
|
| ||||||||||||||
(0.75-
|
(
|
分析:(1)先算小括号里面的加法,再算中括号里面的减法,然后算括号外的除法;
(2)按照从左到右的顺序计算;
(3)先把除法变成乘法,运用乘法交换律简算;
(4)(6)运用乘法分配律简算;
(5)先同时运算小括号里面的减法和加法,再算括号外的乘法.
(2)按照从左到右的顺序计算;
(3)先把除法变成乘法,运用乘法交换律简算;
(4)(6)运用乘法分配律简算;
(5)先同时运算小括号里面的减法和加法,再算括号外的乘法.
解答:解:(1)
÷[
-(
+
)],
=
÷[
-
-
],
=
÷[
-
],
=
÷
,
=
;
(2)
×
×
,
=
×
,
=
;
(3)
÷
÷
,
=
×
×
,
=
×
×
,
=1×
,
=
;
(4)
×
+
×
,
=
×(
+
),
=
×1,
=
;
(5)(0.75-
)×(
+
),
=
×
,
=
;
(6)(
+
)×54,
=
×54+
×54,
=42+10,
=52.
| 4 |
| 9 |
| 4 |
| 5 |
| 1 |
| 5 |
| 1 |
| 3 |
=
| 4 |
| 9 |
| 4 |
| 5 |
| 1 |
| 5 |
| 1 |
| 3 |
=
| 4 |
| 9 |
| 3 |
| 5 |
| 1 |
| 3 |
=
| 4 |
| 9 |
| 4 |
| 15 |
=
| 5 |
| 3 |
(2)
| 8 |
| 15 |
| 5 |
| 6 |
| 4 |
| 9 |
=
| 4 |
| 9 |
| 4 |
| 9 |
=
| 16 |
| 81 |
(3)
| 5 |
| 6 |
| 2 |
| 3 |
| 5 |
| 6 |
=
| 5 |
| 6 |
| 3 |
| 2 |
| 6 |
| 5 |
=
| 5 |
| 6 |
| 6 |
| 5 |
| 3 |
| 2 |
=1×
| 3 |
| 2 |
=
| 3 |
| 2 |
(4)
| 5 |
| 6 |
| 7 |
| 8 |
| 5 |
| 6 |
| 1 |
| 8 |
=
| 5 |
| 6 |
| 7 |
| 8 |
| 1 |
| 8 |
=
| 5 |
| 6 |
=
| 5 |
| 6 |
(5)(0.75-
| 3 |
| 16 |
| 2 |
| 9 |
| 1 |
| 3 |
=
| 9 |
| 16 |
| 5 |
| 9 |
=
| 5 |
| 16 |
(6)(
| 7 |
| 9 |
| 5 |
| 27 |
=
| 7 |
| 9 |
| 5 |
| 27 |
=42+10,
=52.
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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