题目内容
计算,能简算的要简算.
6.12+
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|
|
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|
|
|
|
分析:(1)(3)根据加法交换律和加法结合律进行计算;
(2)(4)(7)根据减法的性质进行计算;
(5)(6)先通分,再计算;
(8)先算括号里面的,再算加法.
(2)(4)(7)根据减法的性质进行计算;
(5)(6)先通分,再计算;
(8)先算括号里面的,再算加法.
解答:解:(1)6.12+
+2.88+
,
=(6.12+2.88)+(
+
),
=9+1,
=10;
(2)
-(
-
),
=
-
+
,
=1+
,
=1
;
(3)
+
+
-
,
=(
+
)+(
-
),
=1+0,
=1;
(4)
-
-
,
=
-(
+
),
=
-1,
=
;
(5)
+
+
,
=
+
+
,
=
;
(6)
-
+
,
=
-
+
,
=
;
(7)
-(
-
),
=
-
,
=
;
(8)
+(
-
),
=
-
,
=
.
| 3 |
| 7 |
| 4 |
| 7 |
=(6.12+2.88)+(
| 3 |
| 7 |
| 4 |
| 7 |
=9+1,
=10;
(2)
| 29 |
| 24 |
| 5 |
| 24 |
| 4 |
| 9 |
=
| 29 |
| 24 |
| 5 |
| 24 |
| 4 |
| 9 |
=1+
| 4 |
| 9 |
=1
| 4 |
| 9 |
(3)
| 7 |
| 15 |
| 7 |
| 12 |
| 8 |
| 15 |
| 7 |
| 12 |
=(
| 7 |
| 15 |
| 8 |
| 15 |
| 7 |
| 12 |
| 7 |
| 12 |
=1+0,
=1;
(4)
| 15 |
| 11 |
| 3 |
| 8 |
| 5 |
| 8 |
=
| 15 |
| 11 |
| 3 |
| 8 |
| 5 |
| 8 |
=
| 15 |
| 11 |
=
| 4 |
| 11 |
(5)
| 5 |
| 6 |
| 7 |
| 9 |
| 3 |
| 8 |
=
| 60 |
| 72 |
| 56 |
| 72 |
| 27 |
| 72 |
=
| 143 |
| 72 |
(6)
| 5 |
| 8 |
| 2 |
| 5 |
| 1 |
| 4 |
=
| 25 |
| 40 |
| 16 |
| 40 |
| 10 |
| 40 |
=
| 19 |
| 40 |
(7)
| 14 |
| 15 |
| 2 |
| 3 |
| 1 |
| 5 |
=
| 14 |
| 15 |
| 7 |
| 15 |
=
| 7 |
| 15 |
(8)
| 19 |
| 20 |
| 4 |
| 5 |
| 7 |
| 40 |
=
| 19 |
| 20 |
| 25 |
| 40 |
=
| 13 |
| 40 |
点评:本题主要考查了学生四则运算的计算能力,以及有计算中灵活运用简便算法的计算能力.
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