题目内容
脱式计算.
①3.68×[1÷(2
-2.09)]
②[
-0÷(
+
)]×1
③1
×
+
÷
④2
+1
×
+
.
①3.68×[1÷(2
1 |
10 |
②[
3 |
4 |
1 |
7 |
2 |
13 |
1 |
3 |
③1
1 |
5 |
3 |
8 |
5 |
8 |
5 |
6 |
④2
1 |
7 |
1 |
8 |
5 |
9 |
3 |
8 |
分析:算式①②④按照四则混合运算的顺序进行计算,先计算中括号内部的再计算括号外面的.
算式③运用乘法的分配律进行计算,使计算更加简便.
算式③运用乘法的分配律进行计算,使计算更加简便.
解答:解:①3.68×[1÷(2
-2.09)],
=3.68×[1÷(
-
)],
=3.68×[1÷(
-
)],
=3.68×[1÷
],
=3.68×100,
=368;
②[
-0÷(
+
)]×1
,
=[
-0]×
,
=
×
,
=1;
③1
×
+
÷
,
=
×
+
×
,
=
×(
+
),
=
×1,
=1
;
④2
+1
×
+
,
=2
+
×
+
,
=2
+(
+
),
=2
+1,
=3
.
1 |
10 |
=3.68×[1÷(
1 |
10 |
9 |
100 |
=3.68×[1÷(
10 |
100 |
9 |
100 |
=3.68×[1÷
1 |
100 |
=3.68×100,
=368;
②[
3 |
4 |
1 |
7 |
2 |
13 |
1 |
3 |
=[
3 |
4 |
4 |
3 |
=
3 |
4 |
4 |
3 |
=1;
③1
1 |
5 |
3 |
8 |
5 |
8 |
5 |
6 |
=
6 |
5 |
3 |
8 |
5 |
8 |
6 |
5 |
=
6 |
5 |
3 |
8 |
5 |
8 |
=
6 |
5 |
=1
1 |
5 |
④2
1 |
7 |
1 |
8 |
5 |
9 |
3 |
8 |
=2
1 |
7 |
9 |
8 |
5 |
9 |
3 |
8 |
=2
1 |
7 |
5 |
8 |
3 |
8 |
=2
1 |
7 |
=3
1 |
7 |
点评:考查了运算定律与简便运算,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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