题目内容
14.76-5.76-
|
4
| ||||||||||||||||||||||
64
|
6
| ||||||||||||||||||||||
13×
|
198÷198
| ||||||||||||||||||||||
12.5×
|
| ||||||||||||||||||||||
(3.7×5
|
[0.3+(
| ||||||||||||||||||||||
56×
|
18.75-(4.5-7.25) | ||||||||||||||||||||||
3.6×31
|
132
| ||||||||||||||||||||||
3×
|
112×(24-4
| ||||||||||||||||||||||
(81.4+
|
41.2×8.1+11×9
| ||||||||||||||||||||||
|
|
分析:(1)按照从左向右的顺序进行计算;
(2)按照从左向右的顺序进行计算;
(3)把带分数化成假分数,再约分计算;
(4)根据乘法分配律进行计算;
(5)先算乘法,再算减法;
(6)先算乘法,再算加法;
(7)根据乘法分配律进行计算;
(8)根据分数的拆项进行计算;
(9)小括号里面的根据乘法分配律进行计算,再算除法;
(10)把□看作未知数,根据等式的性质进行解方程即可;
(11)根据乘法分配律进行计算;
(12)去掉括号,再根据加法交换律进行计算;
(13)根据乘法分配律进行计算;
(14)根据乘法分配律进行计算;
(15)根据加法交换律和结合律进行计算;
(16)根据乘法分配律进行计算;
(17)先算小括号里面的加法,根据乘法分配律进行计算;
(18)根据乘法分配律进行计算;
(19)根据分数的拆项进行计算;
(20)根据分数的拆项进行计算.
(2)按照从左向右的顺序进行计算;
(3)把带分数化成假分数,再约分计算;
(4)根据乘法分配律进行计算;
(5)先算乘法,再算减法;
(6)先算乘法,再算加法;
(7)根据乘法分配律进行计算;
(8)根据分数的拆项进行计算;
(9)小括号里面的根据乘法分配律进行计算,再算除法;
(10)把□看作未知数,根据等式的性质进行解方程即可;
(11)根据乘法分配律进行计算;
(12)去掉括号,再根据加法交换律进行计算;
(13)根据乘法分配律进行计算;
(14)根据乘法分配律进行计算;
(15)根据加法交换律和结合律进行计算;
(16)根据乘法分配律进行计算;
(17)先算小括号里面的加法,根据乘法分配律进行计算;
(18)根据乘法分配律进行计算;
(19)根据分数的拆项进行计算;
(20)根据分数的拆项进行计算.
解答:解:
(1)14.76-5.76-
,
=9-
,
=8
;
(2)4
÷8
×2
,
=
×
×
,
=
;
(3)64
×
,
=
×
,
=
;
(4)6
×5-3
×2,
=(6+
)×5-(3+
)×2,
=(6×5+
×5)-(3×2+
×2),
=30+
-6-
,
=(30-6)+(
-
),
=24+
,
=26
;
(5)13×
+4
×10,
=5
+46,
=51
;
(6)198÷198
+
,
=198×
+
,
=
+
,
=1;
(7)12.5×
+3
×1.25,
=1.25×10×
+3
×1.25,
=1.25×
+3
×1.25,
=1.25×(
+3
),
=1.25×5,
=6.25;
(8)
+
+
+
,
=
+
+
+
,
=1-
+
-
+
-
+
-
,
=1-
,
=
;
(9)(3.7×5
-4.7×3.7)÷
,
=3.7×(5
-4.7)÷
,
=3.7×1÷
,
=3.7÷
,
=11.1;
(10)[0.3+(
+□)×3]÷0.3=860,
[0.3+(
+□)×3]÷0.3=860,
[0.3+1.5+□×3]÷0.3=860,
[1.8+□×3]÷0.3=860,
6+10×□=860,
10×□=854,
□=85.4;
(11)56×
,
=(55+1)×
,
=55×
+1×
,
=54+
,
=54
,
(12)18.75-(4.5-7.25),
=18.75-4.5+7.25,
=(18.75+7.25)-4.5,
=26-4.5,
=21.5;
(13)3.6×31
+3.14×64,
=3.6×31.4+3.14×64,
=3.6×31.4+31.4×6.4,
=(3.6+6.4)×31.4,
=10×31.4,
=314;
(14)132
÷131,
=(131+1
)×
,
=131×
+1
×
,
=1+
×
,
=1+
,
=1
;
(15)3×
+4×
+5×
+6×
,
=(3×
+5×
)+(4×
+6×
),
=
+
,
=2+6,
=8;
(16)112×(24-4
)÷2.4,
=112×(24-4.8)×
,
=112×(24×
-4.8×
),
=112×(10-2),
=112×8,
=896;
(17)(81.4+
+
+
)÷(
+
+
),
=(81.4+
)÷
,
=(81.4+
)×
,
=81.4×
+
×
,
=132+1,
=133;
(18)41.2×8.1+11×9
+53.7×1.9,
=41.2×8.1+11×9.25+(41.2+12.5)×1.9,
=41.2×8.1+11×9.25+41.2×1.9+12.5×1.9,
=(41.2×8.1+41.2×1.9)+11×9.25+12.5×1.9,
=41.2×(8.1+1.9)+11×(8+1.25)+12.5×1.9,
=41.2×10+11×8+11×1.25+1.25×19;
=412+88+1.25×(11+19),
=500+1.25×30,
=500+37.5,
=537.5;
(19)
+
+
+
+
+
+
,
=
+
+
+
+
+
+
,
=1-
+
-
+
-
+
-
+
-
+
-
+
-
,
=1-
,
=
;
(20)
+
+
+…+
,
=
×(1-
+
-
+
-
+…+
-
),
=
×(1-
),
=
×
,
=
.
(1)14.76-5.76-
8 |
9 |
=9-
8 |
9 |
=8
1 |
9 |
(2)4
4 |
9 |
8 |
11 |
2 |
11 |
=
40 |
9 |
11 |
96 |
24 |
11 |
=
10 |
9 |
(3)64
1 |
17 |
1 |
9 |
=
1089 |
17 |
1 |
9 |
=
121 |
17 |
(4)6
12 |
13 |
25 |
26 |
=(6+
12 |
13 |
25 |
26 |
=(6×5+
12 |
13 |
25 |
26 |
=30+
60 |
13 |
25 |
13 |
=(30-6)+(
60 |
13 |
25 |
13 |
=24+
35 |
13 |
=26
9 |
13 |
(5)13×
5 |
12 |
3 |
5 |
=5
5 |
12 |
=51
5 |
12 |
(6)198÷198
198 |
199 |
1 |
200 |
=198×
199 |
198×199+198 |
1 |
200 |
=
199 |
200 |
1 |
200 |
=1;
(7)12.5×
1 |
8 |
3 |
4 |
=1.25×10×
1 |
8 |
3 |
4 |
=1.25×
5 |
4 |
3 |
4 |
=1.25×(
5 |
4 |
3 |
4 |
=1.25×5,
=6.25;
(8)
2 |
3 |
2 |
15 |
2 |
35 |
2 |
63 |
=
2 |
1×3 |
2 |
3×5 |
2 |
5×7 |
2 |
7×9 |
=1-
1 |
3 |
1 |
3 |
1 |
5 |
1 |
5 |
1 |
7 |
1 |
7 |
1 |
9 |
=1-
1 |
9 |
=
8 |
9 |
(9)(3.7×5
7 |
10 |
1 |
3 |
=3.7×(5
7 |
10 |
1 |
3 |
=3.7×1÷
1 |
3 |
=3.7÷
1 |
3 |
=11.1;
(10)[0.3+(
1 |
2 |
[0.3+(
1 |
2 |
[0.3+1.5+□×3]÷0.3=860,
[1.8+□×3]÷0.3=860,
6+10×□=860,
10×□=854,
□=85.4;
(11)56×
54 |
55 |
=(55+1)×
54 |
55 |
=55×
54 |
55 |
54 |
55 |
=54+
54 |
55 |
=54
54 |
55 |
(12)18.75-(4.5-7.25),
=18.75-4.5+7.25,
=(18.75+7.25)-4.5,
=26-4.5,
=21.5;
(13)3.6×31
2 |
5 |
=3.6×31.4+3.14×64,
=3.6×31.4+31.4×6.4,
=(3.6+6.4)×31.4,
=10×31.4,
=314;
(14)132
1 |
130 |
=(131+1
1 |
130 |
1 |
131 |
=131×
1 |
131 |
1 |
130 |
1 |
131 |
=1+
131 |
130 |
1 |
131 |
=1+
1 |
130 |
=1
1 |
130 |
(15)3×
2 |
13 |
3 |
7 |
4 |
13 |
5 |
7 |
=(3×
2 |
13 |
4 |
13 |
3 |
7 |
5 |
7 |
=
26 |
13 |
42 |
7 |
=2+6,
=8;
(16)112×(24-4
4 |
5 |
=112×(24-4.8)×
5 |
12 |
=112×(24×
5 |
12 |
5 |
12 |
=112×(10-2),
=112×8,
=896;
(17)(81.4+
1 |
6 |
1 |
4 |
1 |
5 |
1 |
4 |
1 |
5 |
1 |
6 |
=(81.4+
37 |
60 |
37 |
60 |
=(81.4+
37 |
60 |
60 |
37 |
=81.4×
60 |
37 |
37 |
60 |
60 |
37 |
=132+1,
=133;
(18)41.2×8.1+11×9
1 |
4 |
=41.2×8.1+11×9.25+(41.2+12.5)×1.9,
=41.2×8.1+11×9.25+41.2×1.9+12.5×1.9,
=(41.2×8.1+41.2×1.9)+11×9.25+12.5×1.9,
=41.2×(8.1+1.9)+11×(8+1.25)+12.5×1.9,
=41.2×10+11×8+11×1.25+1.25×19;
=412+88+1.25×(11+19),
=500+1.25×30,
=500+37.5,
=537.5;
(19)
1 |
2 |
1 |
6 |
1 |
12 |
1 |
20 |
1 |
30 |
1 |
42 |
1 |
56 |
=
1 |
1×2 |
1 |
2×3 |
1 |
3×4 |
1 |
4×5 |
1 |
5×6 |
1 |
6×7 |
1 |
7×8 |
=1-
1 |
2 |
1 |
2 |
1 |
3 |
1 |
3 |
1 |
4 |
1 |
4 |
1 |
5 |
1 |
5 |
1 |
6 |
1 |
6 |
1 |
7 |
1 |
7 |
1 |
8 |
=1-
1 |
8 |
=
7 |
8 |
(20)
1 |
1×4 |
1 |
4×7 |
1 |
7×10 |
1 |
97×100 |
=
1 |
3 |
1 |
4 |
1 |
4 |
1 |
7 |
1 |
7 |
1 |
10 |
1 |
97 |
1 |
100 |
=
1 |
3 |
1 |
100 |
=
1 |
3 |
99 |
100 |
=
33 |
100 |
点评:四则运算,先弄清运算顺序,然后再进一步计算,能简算的要简算.
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