题目内容
计算下面各题.(能简便的用简便方法)
|
36×
| ||||||||||
|
1743+2.56-743+7.44. |
分析:(1)先算除法和乘法,再算加法;
(2)先算乘法,然后运用加法结合律简算;
(3)把25%化成分数,1÷4写成分数的形式,运用乘法分配律简算;
(4)运用加法交换律与结合律简算.
(2)先算乘法,然后运用加法结合律简算;
(3)把25%化成分数,1÷4写成分数的形式,运用乘法分配律简算;
(4)运用加法交换律与结合律简算.
解答:解:(1)
÷
+
×
,
=
×
+
×
,
=
+
,
=
;
(2)
+
×
+
,
=
+
+
,
=
+(
+
),
=
+1,
=1
;
(3)36×
+65×25%-1÷4,
=36×
+65×
-
,
=(36+65-1)×
,
=100×
,
=25;
(4)1743+2.56-743+7.44,
=(1743-743)+(2.56+7.44),
=1000+10,
=1010.
3 |
4 |
3 |
5 |
4 |
9 |
3 |
7 |
=
3 |
4 |
5 |
3 |
4 |
9 |
3 |
7 |
=
5 |
4 |
4 |
21 |
=
121 |
84 |
(2)
6 |
7 |
5 |
9 |
3 |
2 |
1 |
6 |
=
6 |
7 |
5 |
6 |
1 |
6 |
=
6 |
7 |
5 |
6 |
1 |
6 |
=
6 |
7 |
=1
6 |
7 |
(3)36×
1 |
4 |
=36×
1 |
4 |
1 |
4 |
1 |
4 |
=(36+65-1)×
1 |
4 |
=100×
1 |
4 |
=25;
(4)1743+2.56-743+7.44,
=(1743-743)+(2.56+7.44),
=1000+10,
=1010.
点评:此题考查了小数、分数的四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算律简便计算.
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