题目内容
递等式计算,能简便计算的要简便计算.
43×99+43
(
+
-
)÷
(8
-10.5×
)÷4
÷[(
+
)÷
].
43×99+43
(
1 |
12 |
7 |
12 |
1 |
2 |
1 |
24 |
(8
5 |
6 |
4 |
5 |
3 |
5 |
1 |
5 |
1 |
3 |
2 |
9 |
分析:(1)43×99+43,应用乘法分配律进行简算;
(2)(
+
-
)÷
,首先根据分数除法的计算法则,把除数转化为乘它的倒数,再应用乘法分配律进行简算;
(3)(8
-10.5×
)÷4
÷[(
+
)÷
].按照分数四则混合运算的运算顺序和四则运算的计算法则进行计算.
(2)(
1 |
12 |
7 |
12 |
1 |
2 |
1 |
24 |
(3)(8
5 |
6 |
4 |
5 |
3 |
5 |
1 |
5 |
1 |
3 |
2 |
9 |
解答:解:(1)43×99+43,
=43×(99+1),
=43×100,
=4300;
(2)(
+
-
)÷
,
=
×24+
×24-
×24,
=2+14-12,
=4;
(3)(8
-10.5×
)÷4
÷[(
+
)÷
].
=(8
-8
)÷
÷[
×
],
=
×
÷
,
=
×
×
,
=
.
=43×(99+1),
=43×100,
=4300;
(2)(
1 |
12 |
7 |
12 |
1 |
2 |
1 |
24 |
=
1 |
12 |
7 |
12 |
1 |
2 |
=2+14-12,
=4;
(3)(8
5 |
6 |
4 |
5 |
3 |
5 |
1 |
5 |
1 |
3 |
2 |
9 |
=(8
5 |
6 |
2 |
5 |
23 |
5 |
8 |
15 |
9 |
2 |
=
13 |
30 |
5 |
23 |
12 |
5 |
=
13 |
30 |
5 |
23 |
5 |
12 |
=
65 |
1656 |
点评:此题是考查四则混合运算,要仔细观察算式的特点,灵活运用一些定律进行简便计算.
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