Question

2、7、8、11算24点

用加减乘除四种运算符号把2、7、8、11算出得数24（每个数字不得重算或遗漏）有几种算法，都写出来啊··急啊···

Answer 1

1: (2 × 7 - 11) × 8
2: ((2 × 7) - 11) × 8
3: (2 - 8) × (7 - 11)
4: 2 × (8 - 7 + 11)
5: 2 × ((8 - 7) + 11)
6: 2 × (8 - (7 - 11))
7: 2 × (8 + 11 - 7)
8: 2 × ((8 + 11) - 7)
9: 2 × (8 + (11 - 7))
10: 2 × (11 - 7 + 8)
11: 2 × ((11 - 7) + 8)
12: 2 × (11 - (7 - 8))
13: 2 × (11 + 8 - 7)
14: 2 × ((11 + 8) - 7)
15: 2 × (11 + (8 - 7))
16: 7 - 2 + 8 + 11
17: (7 - 2) + 8 + 11
18: (7 - 2 + 8) + 11
19: ((7 - 2) + 8) + 11
20: 7 - 2 +(8 + 11)
21: (7 - 2) + (8 + 11)
22: (7 - (2 - 8)) + 11
23: 7 - (2 - 8) + 11
24: 7 - (2 - (8 + 11))
25: 7 - (2 - 8 - 11)
26: 7 - ((2 - 8) - 11)
27: 7 - 2 + 11 + 8
28: (7 - 2) + 11 + 8
29: (7 - 2 + 11) + 8
30: ((7 - 2) + 11) + 8
31: 7 - 2 +(11 + 8)
32: (7 - 2) + (11 + 8)
33: (7 - (2 - 11)) + 8
34: 7 - (2 - 11) + 8
35: 7 - (2 - (11 + 8))
36: 7 - (2 - 11 - 8)
37: 7 - ((2 - 11) - 8)
38: (7 × 2 - 11) × 8
39: ((7 × 2) - 11) × 8
40: 7 + 8 - 2 + 11
41: (7 + 8) - 2 + 11
42: (7 + 8 - 2) + 11
43: ((7 + 8) - 2) + 11
44: (7 + (8 - 2)) + 11
45: 7 + (8 - 2) + 11
46: 7 + (8 - 2 + 11)
47: 7 + ((8 - 2) + 11)
48: 7 + (8 - (2 - 11))
49: 7 + 8 -(2 - 11)
50: (7 + 8) - (2 - 11)
51: 7 + 8 + 11 - 2
52: (7 + 8) + 11 - 2
53: (7 + 8 + 11) - 2
54: ((7 + 8) + 11) - 2
55: (7 + (8 + 11)) - 2
56: 7 + (8 + 11) - 2
57: 7 + (8 + 11 - 2)
58: 7 + ((8 + 11) - 2)
59: 7 + (8 + (11 - 2))
60: 7 + 8 +(11 - 2)
61: (7 + 8) + (11 - 2)
62: 7 + 11 - 2 + 8
63: (7 + 11) - 2 + 8
64: (7 + 11 - 2) + 8
65: ((7 + 11) - 2) + 8
66: (7 + (11 - 2)) + 8
67: 7 + (11 - 2) + 8
68: 7 + (11 - 2 + 8)
69: 7 + ((11 - 2) + 8)
70: 7 + (11 - (2 - 8))
71: 7 + 11 -(2 - 8)
72: (7 + 11) - (2 - 8)
73: (7 - 11) × (2 - 8)
74: 7 + 11 + 8 - 2
75: (7 + 11) + 8 - 2
76: (7 + 11 + 8) - 2
77: ((7 + 11) + 8) - 2
78: (7 + (11 + 8)) - 2
79: 7 + (11 + 8) - 2
80: 7 + (11 + 8 - 2)
81: 7 + ((11 + 8) - 2)
82: 7 + (11 + (8 - 2))
83: 7 + 11 +(8 - 2)
84: (7 + 11) + (8 - 2)
85: 8 - 2 + 7 + 11
86: (8 - 2) + 7 + 11
87: (8 - 2 + 7) + 11
88: ((8 - 2) + 7) + 11
89: 8 - 2 +(7 + 11)
90: (8 - 2) + (7 + 11)
91: (8 - (2 - 7)) + 11
92: 8 - (2 - 7) + 11
93: 8 - (2 - (7 + 11))
94: 8 - (2 - 7 - 11)
95: 8 - ((2 - 7) - 11)
96: 8 × (2 × 7 - 11)
97: 8 × ((2 × 7) - 11)
98: 8 - 2 + 11 + 7
99: (8 - 2) + 11 + 7
100: (8 - 2 + 11) + 7
101: ((8 - 2) + 11) + 7
102: 8 - 2 +(11 + 7)
103: (8 - 2) + (11 + 7)
104: (8 - (2 - 11)) + 7
105: 8 - (2 - 11) + 7
106: 8 - (2 - (11 + 7))
107: 8 - (2 - 11 - 7)
108: 8 - ((2 - 11) - 7)
109: (8 - 2) × (11 - 7)
110: 8 + 7 - 2 + 11
111: (8 + 7) - 2 + 11
112: (8 + 7 - 2) + 11
113: ((8 + 7) - 2) + 11
114: (8 + (7 - 2)) + 11
115: 8 + (7 - 2) + 11
116: 8 + (7 - 2 + 11)
117: 8 + ((7 - 2) + 11)
118: 8 + (7 - (2 - 11))
119: 8 + 7 -(2 - 11)
120: (8 + 7) - (2 - 11)
121: 8 × (7 × 2 - 11)
122: 8 × ((7 × 2) - 11)
123: 8 + 7 + 11 - 2
124: (8 + 7) + 11 - 2
125: (8 + 7 + 11) - 2
126: ((8 + 7) + 11) - 2
127: (8 + (7 + 11)) - 2
128: 8 + (7 + 11) - 2
129: 8 + (7 + 11 - 2)
130: 8 + ((7 + 11) - 2)
131: 8 + (7 + (11 - 2))
132: 8 + 7 +(11 - 2)
133: (8 + 7) + (11 - 2)
134: (8 - 7 + 11) × 2
135: ((8 - 7) + 11) × 2
136: (8 - (7 - 11)) × 2
137: 8 + 11 - 2 + 7
138: (8 + 11) - 2 + 7
139: (8 + 11 - 2) + 7
140: ((8 + 11) - 2) + 7
141: (8 + (11 - 2)) + 7
142: 8 + (11 - 2) + 7
143: 8 + (11 - 2 + 7)
144: 8 + ((11 - 2) + 7)
145: 8 + (11 - (2 - 7))
146: 8 + 11 -(2 - 7)
147: (8 + 11) - (2 - 7)
148: 8 + 11 + 7 - 2
149: (8 + 11) + 7 - 2
150: (8 + 11 + 7) - 2
151: ((8 + 11) + 7) - 2
152: (8 + (11 + 7)) - 2
153: 8 + (11 + 7) - 2
154: 8 + (11 + 7 - 2)
155: 8 + ((11 + 7) - 2)
156: 8 + (11 + (7 - 2))
157: 8 + 11 +(7 - 2)
158: (8 + 11) + (7 - 2)
159: (8 + 11 - 7) × 2
160: ((8 + 11) - 7) × 2
161: (8 + (11 - 7)) × 2
162: 11 - 2 + 7 + 8
163: (11 - 2) + 7 + 8
164: (11 - 2 + 7) + 8
165: ((11 - 2) + 7) + 8
166: 11 - 2 +(7 + 8)
167: (11 - 2) + (7 + 8)
168: (11 - (2 - 7)) + 8
169: 11 - (2 - 7) + 8
170: 11 - (2 - (7 + 8))
171: 11 - (2 - 7 - 8)
172: 11 - ((2 - 7) - 8)
173: 11 - 2 + 8 + 7
174: (11 - 2) + 8 + 7
175: (11 - 2 + 8) + 7
176: ((11 - 2) + 8) + 7
177: 11 - 2 +(8 + 7)
178: (11 - 2) + (8 + 7)
179: (11 - (2 - 8)) + 7
180: 11 - (2 - 8) + 7
181: 11 - (2 - (8 + 7))
182: 11 - (2 - 8 - 7)
183: 11 - ((2 - 8) - 7)
184: 11 + 7 - 2 + 8
185: (11 + 7) - 2 + 8
186: (11 + 7 - 2) + 8
187: ((11 + 7) - 2) + 8
188: (11 + (7 - 2)) + 8
189: 11 + (7 - 2) + 8
190: 11 + (7 - 2 + 8)
191: 11 + ((7 - 2) + 8)
192: 11 + (7 - (2 - 8))
193: 11 + 7 -(2 - 8)
194: (11 + 7) - (2 - 8)
195: 11 + 7 + 8 - 2
196: (11 + 7) + 8 - 2
197: (11 + 7 + 8) - 2
198: ((11 + 7) + 8) - 2
199: (11 + (7 + 8)) - 2
200: 11 + (7 + 8) - 2
201: 11 + (7 + 8 - 2)
202: 11 + ((7 + 8) - 2)
203: 11 + (7 + (8 - 2))
204: 11 + 7 +(8 - 2)
205: (11 + 7) + (8 - 2)
206: (11 - 7 + 8) × 2
207: ((11 - 7) + 8) × 2
208: (11 - (7 - 8)) × 2
209: (11 - 7) × (8 - 2)
210: 11 + 8 - 2 + 7
211: (11 + 8) - 2 + 7
212: (11 + 8 - 2) + 7
213: ((11 + 8) - 2) + 7
214: (11 + (8 - 2)) + 7
215: 11 + (8 - 2) + 7
216: 11 + (8 - 2 + 7)
217: 11 + ((8 - 2) + 7)
218: 11 + (8 - (2 - 7))
219: 11 + 8 -(2 - 7)
220: (11 + 8) - (2 - 7)
221: 11 + 8 + 7 - 2
222: (11 + 8) + 7 - 2
223: (11 + 8 + 7) - 2
224: ((11 + 8) + 7) - 2
225: (11 + (8 + 7)) - 2
226: 11 + (8 + 7) - 2
227: 11 + (8 + 7 - 2)
228: 11 + ((8 + 7) - 2)
229: 11 + (8 + (7 - 2))
230: 11 + 8 +(7 - 2)
231: (11 + 8) + (7 - 2)
232: (11 + 8 - 7) × 2
233: ((11 + 8) - 7) × 2
234: (11 + (8 - 7)) × 2

Answer 2

(2*7-11)*8=24
(11-7)*(8-2)=24
2*(8+11-7)=24
就三种，也就是24能分成哪两个数相乘
2*12,3*8和4*6

1*24没有

Answer 3

（11-7）*（8-2）=24

Answer 4

11+8+7-2=24
(8-2)*(11-7)=24

Answer 5

2×(11+8-7)=24