题目内容
(2012?铜仁地区)脱式计算,能简算的要简算.
24×(
|
|
| ||||||||||||||||||
|
0.25×32×125 | 256-72+2.4. |
分析:(1)运用乘法分配律简算;
(2)按照从左到右的顺序计算;
(3)先把除法变成乘法,再运用乘法分配律简算;
(4)根据减法的性质简算;
(5)先把32分解成4×8,再运用乘法结合律简算;
(6)按照从左到右的顺序计算.
(2)按照从左到右的顺序计算;
(3)先把除法变成乘法,再运用乘法分配律简算;
(4)根据减法的性质简算;
(5)先把32分解成4×8,再运用乘法结合律简算;
(6)按照从左到右的顺序计算.
解答:解:(1)24×(
+
+
),
=24×
+24×
+24×
,
=18+8+10,
=36;
(2)
+
-
,
=
-
,
=
;
(3)
÷5+
×
,
=
×
+
×
,
=(
+
)×
,
=1×
,
=
;
(4)
-(
-
),
=
+
-
,
=1-
,
=
;
(5)0.25×32×125,
=0.25×4×8×125,
=(0.25×4)×(8×125),
=1×1000,
=1000;
(6)256-72+2.4,
=184+2.4,
=186.4.
3 |
4 |
1 |
3 |
5 |
12 |
=24×
3 |
4 |
1 |
3 |
5 |
12 |
=18+8+10,
=36;
(2)
5 |
12 |
5 |
8 |
5 |
6 |
=
25 |
24 |
20 |
24 |
=
5 |
24 |
(3)
1 |
4 |
3 |
4 |
1 |
5 |
=
1 |
4 |
1 |
5 |
3 |
4 |
1 |
5 |
=(
1 |
4 |
3 |
4 |
1 |
5 |
=1×
1 |
5 |
=
1 |
5 |
(4)
23 |
25 |
15 |
17 |
2 |
25 |
=
23 |
25 |
2 |
25 |
15 |
17 |
=1-
15 |
17 |
=
2 |
17 |
(5)0.25×32×125,
=0.25×4×8×125,
=(0.25×4)×(8×125),
=1×1000,
=1000;
(6)256-72+2.4,
=184+2.4,
=186.4.
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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