题目内容
请你算一算
(1)(3
+4
-1
)÷(1-
)
(2)999.8×98+(
-0.6)×9998
(3)[(3
-3
)×1.5+2.45]×(1.9-
)
(4)解方程:(0.5Χ+4
):
=Χ:0.6.
(1)(3
5 |
6 |
5 |
9 |
1 |
4 |
35 |
36 |
(2)999.8×98+(
4 |
5 |
(3)[(3
1 |
5 |
1 |
6 |
9 |
10 |
(4)解方程:(0.5Χ+4
1 |
2 |
7 |
10 |
分析:(1)、(2)运用乘法的分配律进行计算即可.
(3)我们按照四则混合运算的剩下进行计算,先计算中括号内部的小括号,再就是中括号内部的,最后计算中括号外面的.
(4)我们运用比例的基本性质进行解答即可.
(3)我们按照四则混合运算的剩下进行计算,先计算中括号内部的小括号,再就是中括号内部的,最后计算中括号外面的.
(4)我们运用比例的基本性质进行解答即可.
解答:解:(1)(3
+4
-1
)÷(1-
),
=[6+(
+
-
)]×36,
=6×36+(
+
-
)×36,
=36×6+36×
+36×
-36×
,
=216+30+20-9,
=257;
(2)999.8×98+(
-0.6)×9998,
=999.8×98+0.2×9998,
=999.8×98+2×999.8,
=999.8×(98+2),
=999.8×100,
=99980;
(3)[(3
-3
)×1.5+2.45]×(1.9-
),
=[
×1.5+2.45]×1,
=[0.05+2.45]×1,
=2.5;
(4)(0.5x+4
):
=x:0.6,
0.7x=0.6×(0.5x+4.5)
0.7x=0.3x+2.7,
0.7x-0.3x=0.3x-0.3x+2.7,
0.4x=2.7,
0.4x÷0.4=2.7÷0.4,
x=6.75.
5 |
6 |
5 |
9 |
1 |
4 |
35 |
36 |
=[6+(
5 |
6 |
5 |
9 |
1 |
4 |
=6×36+(
5 |
6 |
5 |
9 |
1 |
4 |
=36×6+36×
5 |
6 |
5 |
9 |
1 |
4 |
=216+30+20-9,
=257;
(2)999.8×98+(
4 |
5 |
=999.8×98+0.2×9998,
=999.8×98+2×999.8,
=999.8×(98+2),
=999.8×100,
=99980;
(3)[(3
1 |
5 |
1 |
6 |
9 |
10 |
=[
1 |
30 |
=[0.05+2.45]×1,
=2.5;
(4)(0.5x+4
1 |
2 |
7 |
10 |
0.7x=0.6×(0.5x+4.5)
0.7x=0.3x+2.7,
0.7x-0.3x=0.3x-0.3x+2.7,
0.4x=2.7,
0.4x÷0.4=2.7÷0.4,
x=6.75.
点评:完成本题要注意分析式中数据,运用合适的简便方法计算.同时考查了比例基本性质的掌握与运用情况.
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