题目内容
计算下面各题,怎样计算简便就怎样计算.
2-(
|
|
|
0.125×32×25. |
分析:(1)先算小括号里面的加法,再算括号外的减法;
(2)运用加法交换律和加法结合律简算;
(3)运用加法结合律简算;
(4)先把32分解成8×4,再运用乘法结合律简算.
(2)运用加法交换律和加法结合律简算;
(3)运用加法结合律简算;
(4)先把32分解成8×4,再运用乘法结合律简算.
解答:解:(1)2-(
+
),
=2-
,
=1
;
(2)
+
+
+
,
=(
+
)+(
+
),
=1+1,
=2;
(3)
-
+
,
=
-(
-
),
=
-
,
=
;
(4)0.125×32×25,
=0.125×8×4×25,
=(0.125×8)×(4×25),
=1×100,
=100.
2 |
9 |
5 |
18 |
=2-
1 |
2 |
=1
1 |
2 |
(2)
1 |
5 |
3 |
8 |
4 |
5 |
5 |
8 |
=(
1 |
5 |
4 |
5 |
3 |
8 |
5 |
8 |
=1+1,
=2;
(3)
8 |
9 |
2 |
3 |
1 |
3 |
=
8 |
9 |
2 |
3 |
1 |
3 |
=
8 |
9 |
1 |
3 |
=
5 |
9 |
(4)0.125×32×25,
=0.125×8×4×25,
=(0.125×8)×(4×25),
=1×100,
=100.
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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