题目内容
计算下面题(能简算的要简算)
(1)8×
+
×8+2÷
(2)
×
+0.45×1.5-45%
(3)
÷
-
×16
(4)
-(40%+
)×
.
(1)8×
3 |
7 |
4 |
7 |
4 |
13 |
(2)
9 |
20 |
1 |
2 |
(3)
8 |
9 |
1 |
18 |
3 |
4 |
(4)
7 |
6 |
3 |
5 |
5 |
6 |
分析:(1)前两个算式利用乘法分配律进行简算,再按顺序解答;
(2)把
化成0.45,把45%也化成0.45,再利用乘法分配律进行简算;
(3)根据四则混合运算的顺序直接进行计算;
(4)把40%化成
,根据分数四则混合运算的顺序进行计算;
(2)把
9 |
20 |
(3)根据四则混合运算的顺序直接进行计算;
(4)把40%化成
2 |
5 |
解答:解:(1)8×
+
×8+2÷
=8×(
+
)+2×
=8×1+6.5
=14.5;
(2)
×
+0.45×1.5-45%
=0.45×0.5+0.45×1.5-0.45
=0.45×(0.5+1.5-1)
=0.45×1
=0.45;
(3)
÷
-
×16
=
×18-
×16
=16-12
=4;
(4)
-(40%+
)×
=
-(
+
)×
=
-1×
=
-
=
.
3 |
7 |
4 |
7 |
4 |
13 |
=8×(
3 |
7 |
4 |
7 |
13 |
4 |
=8×1+6.5
=14.5;
(2)
9 |
20 |
1 |
2 |
=0.45×0.5+0.45×1.5-0.45
=0.45×(0.5+1.5-1)
=0.45×1
=0.45;
(3)
8 |
9 |
1 |
18 |
3 |
4 |
=
8 |
9 |
3 |
4 |
=16-12
=4;
(4)
7 |
6 |
3 |
5 |
5 |
6 |
=
7 |
6 |
2 |
5 |
3 |
5 |
5 |
6 |
=
7 |
6 |
5 |
6 |
=
7 |
6 |
5 |
6 |
=
1 |
3 |
点评:此题主要考查分数四则混合运算的运算顺序和分数四则运算的计算方法,以及利用乘法的运算定律进行简算.
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