1：用3、4、5、7、这四个数和加、减、乘、除括号五种运算符号组成一个算式,要求算式的得数是24,能写几个就写几个算式.

涓夐?鍏ㄧ瓟浜?竴灏忛?鏈夌偣闀军br/>(1).
1:3 脳 4 + 5 + 7
2:(3 脳 4) + 5 + 7
3:(3 脳 4 + 5) + 7
4:((3 脳 4) + 5) + 7
5:3 脳 4 +(5 + 7)
6:(3 脳 4) + (5 + 7)
7:3 脳 4 + 7 + 5
8:(3 脳 4) + 7 + 5
9:(3 脳 4 + 7) + 5
10:((3 脳 4) + 7) + 5
11:3 脳 4 +(7 + 5)
12:(3 脳 4) + (7 + 5)
13:3 脳 (4 脳 (7 - 5))
14:3 脳 4 脳(7 - 5)
15:(3 脳 4) 脳 (7 - 5)
16:3 脳 (5 - 4 + 7)
17:3 脳 ((5 - 4) + 7)
18:3 脳 (5 - (4 - 7))
19:(3 + 5) 脳 (7 - 4)
20:3 脳 (5 + 7 - 4)
21:3 脳 ((5 + 7) - 4)
22:3 脳 (5 + (7 - 4))
23:3 脳 (7 - 4 + 5)
24:3 脳 ((7 - 4) + 5)
25:3 脳 (7 - (4 - 5))
26:3 脳 (7 + 5 - 4)
27:3 脳 ((7 + 5) - 4)
28:3 脳 (7 + (5 - 4))
29:(3 脳 (7 - 5)) 脳 4
30:3 脳 (7 - 5) 脳 4
31:3 脳 ((7 - 5) 脳 4)
32:4 脳 3 + 5 + 7
33:(4 脳 3) + 5 + 7
34:(4 脳 3 + 5) + 7
35:((4 脳 3) + 5) + 7
36:4 脳 3 +(5 + 7)
37:(4 脳 3) + (5 + 7)
38:4 - (3 - 7) 脳 5
39:4 - ((3 - 7) 脳 5)
40:4 脳 3 + 7 + 5
41:(4 脳 3) + 7 + 5
42:(4 脳 3 + 7) + 5
43:((4 脳 3) + 7) + 5
44:4 脳 3 +(7 + 5)
45:(4 脳 3) + (7 + 5)
46:4 脳 (3 脳 (7 - 5))
47:4 脳 3 脳(7 - 5)
48:(4 脳 3) 脳 (7 - 5)
49:4 - (5 脳 (3 - 7))
50:4 - 5 脳(3 - 7)
51:4 脳 5 - 3 + 7
52:(4 脳 5) - 3 + 7
53:(4 脳 5 - 3) + 7
54:((4 脳 5) - 3) + 7
55:4 脳 5 -(3 - 7)
56:(4 脳 5) - (3 - 7)
57:4 + (5 脳 (7 - 3))
58:4 + 5 脳(7 - 3)
59:4 脳 5 + 7 - 3
60:(4 脳 5) + 7 - 3
61:(4 脳 5 + 7) - 3
62:((4 脳 5) + 7) - 3
63:4 脳 5 +(7 - 3)
64:(4 脳 5) + (7 - 3)
65:4 + (7 - 3) 脳 5
66:4 + ((7 - 3) 脳 5)
67:(4 脳 (7 - 5)) 脳 3
68:4 脳 (7 - 5) 脳 3
69:4 脳 ((7 - 5) 脳 3)
70:5 + 3 脳 4 + 7
71:(5 + 3 脳 4) + 7
72:(5 + (3 脳 4)) + 7
73:5 + (3 脳 4) + 7
74:5 + (3 脳 4 + 7)
75:5 + ((3 脳 4) + 7)
76:(5 + 3) 脳 (7 - 4)
77:5 + 4 脳 3 + 7
78:(5 + 4 脳 3) + 7
79:(5 + (4 脳 3)) + 7
80:5 + (4 脳 3) + 7
81:5 + (4 脳 3 + 7)
82:5 + ((4 脳 3) + 7)
83:5 脳 4 - 3 + 7
84:(5 脳 4) - 3 + 7
85:(5 脳 4 - 3) + 7
86:((5 脳 4) - 3) + 7
87:5 脳 4 -(3 - 7)
88:(5 脳 4) - (3 - 7)
89:(5 - 4 + 7) 脳 3
90:((5 - 4) + 7) 脳 3
91:(5 - (4 - 7)) 脳 3
92:5 脳 4 + 7 - 3
93:(5 脳 4) + 7 - 3
94:(5 脳 4 + 7) - 3
95:((5 脳 4) + 7) - 3
96:5 脳 4 +(7 - 3)
97:(5 脳 4) + (7 - 3)
98:5 + 7 + 3 脳 4
99:(5 + 7) + 3 脳 4
100:5 + (7 + 3 脳 4)
101:5 + (7 + (3 脳 4))
102:5 + 7 +(3 脳 4)
103:(5 + 7) + (3 脳 4)
104:(5 脳 (7 - 3)) + 4
105:5 脳 (7 - 3) + 4
106:5 + 7 + 4 脳 3
107:(5 + 7) + 4 脳 3
108:5 + (7 + 4 脳 3)
109:5 + (7 + (4 脳 3))
110:5 + 7 +(4 脳 3)
111:(5 + 7) + (4 脳 3)
112:(5 + 7 - 4) 脳 3
113:((5 + 7) - 4) 脳 3
114:(5 + (7 - 4)) 脳 3
115:7 + 3 脳 4 + 5
116:(7 + 3 脳 4) + 5
117:(7 + (3 脳 4)) + 5
118:7 + (3 脳 4) + 5
119:7 + (3 脳 4 + 5)
120:7 + ((3 脳 4) + 5)
121:7 - 3 + 4 脳 5
122:(7 - 3) + 4 脳 5
123:7 - 3 +(4 脳 5)
124:(7 - 3) + (4 脳 5)
125:7 - (3 - 4 脳 5)
126:7 - (3 - (4 脳 5))
127:7 - 3 + 5 脳 4
128:(7 - 3) + 5 脳 4
129:7 - 3 +(5 脳 4)
130:(7 - 3) + (5 脳 4)
131:7 - (3 - 5 脳 4)
132:7 - (3 - (5 脳 4))
133:(7 - 3) 脳 5 + 4
134:((7 - 3) 脳 5) + 4
135:7 + 4 脳 3 + 5
136:(7 + 4 脳 3) + 5
137:(7 + (4 脳 3)) + 5
138:7 + (4 脳 3) + 5
139:7 + (4 脳 3 + 5)
140:7 + ((4 脳 3) + 5)
141:(7 - 4) 脳 (3 + 5)
142:7 + 4 脳 5 - 3
143:(7 + 4 脳 5) - 3
144:(7 + (4 脳 5)) - 3
145:7 + (4 脳 5) - 3
146:7 + (4 脳 5 - 3)
147:7 + ((4 脳 5) - 3)
148:(7 - 4 + 5) 脳 3
149:((7 - 4) + 5) 脳 3
150:(7 - (4 - 5)) 脳 3
151:(7 - 4) 脳 (5 + 3)
152:7 + 5 + 3 脳 4
153:(7 + 5) + 3 脳 4
154:7 + (5 + 3 脳 4)
155:7 + (5 + (3 脳 4))
156:7 + 5 +(3 脳 4)
157:(7 + 5) + (3 脳 4)
158:(7 - 5) 脳 3 脳 4
159:((7 - 5) 脳 3) 脳 4
160:(7 - 5) 脳 (3 脳 4)
161:7 + 5 + 4 脳 3
162:(7 + 5) + 4 脳 3
163:7 + (5 + 4 脳 3)
164:7 + (5 + (4 脳 3))
165:7 + 5 +(4 脳 3)
166:(7 + 5) + (4 脳 3)
167:(7 + 5 - 4) 脳 3
168:((7 + 5) - 4) 脳 3
169:(7 + (5 - 4)) 脳 3
170:7 + 5 脳 4 - 3
171:(7 + 5 脳 4) - 3
172:(7 + (5 脳 4)) - 3
173:7 + (5 脳 4) - 3
174:7 + (5 脳 4 - 3)
175:7 + ((5 脳 4) - 3)
176:(7 - 5) 脳 4 脳 3
177:((7 - 5) 脳 4) 脳 3
178:(7 - 5) 脳 (4 脳 3)
(2)瑙Ⅹ璁剧敳鏁颁负x,鍒欎箼鏁颁负1/10x
x+1/10x=264
x=240
绛擔鐢叉暟涓?40,涔欐暟涓?4
(3)瑙Ⅹ璁炬补閲峹鍗冨厠,鍒欐《閲?6.5-x)鍗冨厠
(6.5-x)+1/2x=3.5
x=6
绛擔娌归噸6鍗冨厠,妗堕噸0.5鍗冨厠
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