题目内容
脱式计算:
(1)0.25×〔
÷(4-2.4×
)〕
(2)〔1
-8.19÷(5.25+1
)〕×
÷17%
(3)6
-(5
-1
)+1
(4)4.83×0.59+0.41×1.59-0.324×5.9
(5)5.6-(□×3
-1
×□)÷5
=2
,□=
(1)0.25×〔
7 |
20 |
5 |
6 |
(2)〔1
4 |
9 |
3 |
4 |
9 |
13 |
(3)6
7 |
13 |
3 |
7 |
7 |
13 |
4 |
7 |
(4)4.83×0.59+0.41×1.59-0.324×5.9
(5)5.6-(□×3
1 |
4 |
5 |
6 |
2 |
3 |
3 |
5 |
12
12
.分析:(1)、(2)、(3)按整数、分数、小数、百分数四则混合运算的运算顺序和计算法则进行计算;
(4)把0.324×5.9变成3.24×0.59后先运用乘法分配律计算4.83×0.59-3.24×0.59,得到1.59×0.59,然后再运用乘法分配律进行简算;
(5)“□”为未知数,用解方程的解题思路求解.
(4)把0.324×5.9变成3.24×0.59后先运用乘法分配律计算4.83×0.59-3.24×0.59,得到1.59×0.59,然后再运用乘法分配律进行简算;
(5)“□”为未知数,用解方程的解题思路求解.
解答:解:(1)0.25×〔
÷(4-2.4×
)〕,
=0.25×〔
÷(4-
×
)〕,
=0.25×〔
÷(4-2)〕,
=0.25×〔
÷2〕,
=
×
,
=
;
(2)〔1
-8.19÷(5.25+1
)〕×
÷17%,
=〔1
-8.19÷(5.25+1.75)〕×
÷17%,
=〔1
-8.19÷7〕×
÷17%,
=〔1
-1.17〕×
×
,
=(
-
)×
×
,
=
×
×
-
×
×
,
=
-
,
=
-
=
;
(3)6
-(5
-1
)+1
,
=6
-5
+1
+1
,
=6
-5
+1
+1
,
=1
+1
+1
,
=4
;
(4)4.83×0.59+0.41×1.59-0.324×5.9,
=4.83×0.59+0.41×1.59-3.24×0.59,
=(4.83-3.24)×0.59+0.41×1.59,
=1.59×0.59+0.41×1.59,
=(0.59+0.41)×1.59,
=1×1.59,
=1.59;
(5)5.6-(□×3
-1
×□)÷5
=2
,
5.6-(
×□)÷5
=2
,
5.6-(
×□)×
=2
,
5.6-
×□=2
,
×□=5.6-2.6,
□=3÷
,
□=12.
故答案为:(1)
;(2)
;(3)4
;(4)1.59;(5)12.
7 |
20 |
5 |
6 |
=0.25×〔
7 |
20 |
12 |
5 |
5 |
6 |
=0.25×〔
7 |
20 |
=0.25×〔
7 |
20 |
=
1 |
4 |
7 |
40 |
=
7 |
160 |
(2)〔1
4 |
9 |
3 |
4 |
9 |
13 |
=〔1
4 |
9 |
9 |
13 |
=〔1
4 |
9 |
9 |
13 |
=〔1
4 |
9 |
9 |
13 |
100 |
17 |
=(
4 |
9 |
17 |
100 |
9 |
13 |
100 |
17 |
=
4 |
9 |
9 |
13 |
100 |
17 |
17 |
100 |
9 |
13 |
100 |
17 |
=
400 |
221 |
9 |
13 |
=
400 |
221 |
153 |
221 |
=
247 |
221 |
(3)6
7 |
13 |
3 |
7 |
7 |
13 |
4 |
7 |
=6
7 |
13 |
3 |
7 |
7 |
13 |
4 |
7 |
=6
49 |
91 |
39 |
91 |
49 |
91 |
52 |
91 |
=1
10 |
91 |
49 |
91 |
52 |
91 |
=4
7 |
13 |
(4)4.83×0.59+0.41×1.59-0.324×5.9,
=4.83×0.59+0.41×1.59-3.24×0.59,
=(4.83-3.24)×0.59+0.41×1.59,
=1.59×0.59+0.41×1.59,
=(0.59+0.41)×1.59,
=1×1.59,
=1.59;
(5)5.6-(□×3
1 |
4 |
5 |
6 |
2 |
3 |
3 |
5 |
5.6-(
17 |
12 |
2 |
3 |
3 |
5 |
5.6-(
17 |
12 |
3 |
17 |
3 |
5 |
5.6-
1 |
4 |
3 |
5 |
1 |
4 |
□=3÷
1 |
4 |
□=12.
故答案为:(1)
7 |
160 |
247 |
221 |
7 |
13 |
点评:此题考查整数、分数、小数、百分数四则混合运算,按计算法则计算,同时注意运用定律进行简算.
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