题目内容
脱式计算,能简算的要简算.
(1)
÷(
÷
+
)
(2)
×
÷
÷
(3)
×13+
×13
(4)
(5)(
+
)×9×17
(6)
+
+
+
+
+
.
(1)
15 |
16 |
5 |
12 |
5 |
8 |
3 |
8 |
(2)
1 |
7 |
9 |
13 |
5 |
14 |
3 |
13 |
(3)
7 |
19 |
13 |
19 |
(4)
1993×1994×1995 |
1993×1992×1994 |
(5)(
2 |
51 |
5 |
18 |
(6)
1 |
42 |
1 |
56 |
1 |
72 |
1 |
90 |
1 |
110 |
1 |
132 |
分析:(1)依据四则混合运算的运算顺序计算,
(2)化除法为乘法,再运用乘法交换律和结合律计算,
(3)(5)运用乘法分配律计算,
(4)依据分数基本性质,分子分母约分计算,
(6)化
=
-
,
=
-
,
=
-
,
=
-
,
=
-
,
=
-
即可解答.
(2)化除法为乘法,再运用乘法交换律和结合律计算,
(3)(5)运用乘法分配律计算,
(4)依据分数基本性质,分子分母约分计算,
(6)化
1 |
42 |
1 |
6 |
1 |
7 |
1 |
56 |
1 |
7 |
1 |
8 |
1 |
72 |
1 |
8 |
1 |
9 |
1 |
90 |
1 |
9 |
1 |
10 |
1 |
110 |
1 |
10 |
1 |
11 |
1 |
132 |
1 |
11 |
1 |
12 |
解答:解:(1)
÷(
÷
+
),
=
÷(
+
),
÷
,
=
;
(2)
×
÷
÷
,
=(
×
)×(
×
),
=
×3,
=1
;
(3)
×13+
×13,
=(
+
)×13,
=1
×13,
=13
;
(4)
=1
;
(5)(
+
)×9×17,
=
×9×17+
×9×17,
=6+42
,
=48
;
(6)
+
+
+
+
+
,
=
-
+
-
+
-
+
-
+
-
+
-
,
=
-
,
=
.
15 |
16 |
5 |
12 |
5 |
8 |
3 |
8 |
=
15 |
16 |
2 |
3 |
3 |
8 |
15 |
16 |
25 |
24 |
=
9 |
10 |
(2)
1 |
7 |
9 |
13 |
5 |
14 |
3 |
13 |
=(
1 |
7 |
14 |
5 |
9 |
13 |
13 |
3 |
=
2 |
5 |
=1
1 |
5 |
(3)
7 |
19 |
13 |
19 |
=(
7 |
19 |
13 |
19 |
=1
1 |
19 |
=13
13 |
19 |
(4)
1993×1994×1995 |
1993×1992×1994 |
3 |
1992 |
(5)(
2 |
51 |
5 |
18 |
=
2 |
51 |
5 |
18 |
=6+42
1 |
2 |
=48
1 |
2 |
(6)
1 |
42 |
1 |
56 |
1 |
72 |
1 |
90 |
1 |
110 |
1 |
132 |
=
1 |
6 |
1 |
7 |
1 |
7 |
1 |
8 |
1 |
8 |
1 |
9 |
1 |
9 |
1 |
10 |
1 |
10 |
1 |
11 |
1 |
11 |
1 |
12 |
=
1 |
6 |
1 |
12 |
=
1 |
12 |
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,没有简便算法的要正确按照四则混合运算的运算顺序计算,注意计算结果的准确性.
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