题目内容
脱式计算 ①
|
②
|
③(
| ||||||||||||||||||||||||
④(
|
⑤45×
|
⑥27×
|
分析:①先算乘法,再算加法,最后算减法;
②先算小括号里面的减法,再算括号外的乘法,最后算括号外的加法;
③先同时运算两个小括号里面的减法和加法,再算括号外的乘法;
④先算小括号里面的乘法,再算括号外的乘法;
⑤⑥运用乘法分配律简算.
②先算小括号里面的减法,再算括号外的乘法,最后算括号外的加法;
③先同时运算两个小括号里面的减法和加法,再算括号外的乘法;
④先算小括号里面的乘法,再算括号外的乘法;
⑤⑥运用乘法分配律简算.
解答:解:①
+
×
-
,
=
+
-
,
=
-
,
=
;
②
+(
-
)×
,
=
+
×
,
=
+
,
=
;
③(
-
)×(
+
),
=
×
,
=
;
④(
×
)×24,
=
×24,
=
;
⑤45×
-
×45,
=(45-45)×
,
=0×
,
=0;
⑥27×
+27÷5,
=27×
+27×
,
=27×(
+
),
=27×1,
=27.
1 |
16 |
1 |
2 |
5 |
8 |
1 |
3 |
=
1 |
16 |
5 |
16 |
1 |
3 |
=
3 |
8 |
1 |
3 |
=
1 |
24 |
②
1 |
2 |
3 |
4 |
1 |
12 |
3 |
5 |
=
1 |
2 |
2 |
3 |
3 |
5 |
=
1 |
2 |
2 |
5 |
=
9 |
10 |
③(
7 |
9 |
5 |
18 |
3 |
4 |
5 |
8 |
=
1 |
2 |
11 |
8 |
=
11 |
16 |
④(
1 |
6 |
3 |
8 |
=
1 |
16 |
=
3 |
2 |
⑤45×
4 |
9 |
4 |
9 |
=(45-45)×
4 |
9 |
=0×
4 |
9 |
=0;
⑥27×
4 |
5 |
=27×
4 |
5 |
1 |
5 |
=27×(
4 |
5 |
1 |
5 |
=27×1,
=27.
点评:此题主要考查分数的四则混合运算的运算顺序,以及应用运算定律进行简便计算的能力.
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