钟面上有1~12个数字,你能在某些数的前面添上负号,使添号后的12个数之和等于零,看悬赏!

钟面上有1~12个数字,你能在某些数的前面添上负号,使添号后的12个数之和等于零。问:共有几种添法?

124种:

1+2+3+4+5+6+7-8-9-10+11-12 = 0
1+2+3+4+5+6-7+8-9+10-11-12 = 0
1+2+3+4+5-6+7+8+9-10-11-12 = 0
1+2+3+4-5+6-7-8-9-10+11+12 = 0
1+2+3+4-5-6+7-8-9+10-11+12 = 0
1+2+3+4-5-6-7+8+9-10-11+12 = 0
1+2+3+4-5-6-7+8-9+10+11-12 = 0
1+2+3-4+5+6-7-8-9+10-11+12 = 0
1+2+3-4+5-6+7-8+9-10-11+12 = 0
1+2+3-4+5-6+7-8-9+10+11-12 = 0
1+2+3-4+5-6-7+8+9-10+11-12 = 0
1+2+3-4-5+6+7+8-9-10-11+12 = 0
1+2+3-4-5+6+7-8+9-10+11-12 = 0
1+2+3-4-5+6-7+8+9+10-11-12 = 0
1+2+3-4-5-6-7-8-9+10+11+12 = 0
1+2-3+4+5+6-7-8+9-10-11+12 = 0
1+2-3+4+5+6-7-8-9+10+11-12 = 0
1+2-3+4+5-6+7+8-9-10-11+12 = 0
1+2-3+4+5-6+7-8+9-10+11-12 = 0
1+2-3+4+5-6-7+8+9+10-11-12 = 0
1+2-3+4-5+6+7+8-9-10+11-12 = 0
1+2-3+4-5+6+7-8+9+10-11-12 = 0
1+2-3+4-5-6-7-8+9-10+11+12 = 0
1+2-3-4+5+6+7+8-9+10-11-12 = 0
1+2-3-4+5-6-7+8-9-10+11+12 = 0
1+2-3-4+5-6-7-8+9+10-11+12 = 0
1+2-3-4-5+6+7-8-9-10+11+12 = 0
1+2-3-4-5+6-7+8-9+10-11+12 = 0
1+2-3-4-5+6-7-8+9+10+11-12 = 0
1+2-3-4-5-6+7+8+9-10-11+12 = 0
1+2-3-4-5-6+7+8-9+10+11-12 = 0
1-2+3+4+5+6-7+8-9-10-11+12 = 0
1-2+3+4+5+6-7-8+9-10+11-12 = 0
1-2+3+4+5-6+7+8-9-10+11-12 = 0
1-2+3+4+5-6+7-8+9+10-11-12 = 0
1-2+3+4-5+6+7+8-9+10-11-12 = 0
1-2+3+4-5-6-7+8-9-10+11+12 = 0
1-2+3+4-5-6-7-8+9+10-11+12 = 0
1-2+3-4+5+6+7+8+9-10-11-12 = 0
1-2+3-4+5-6+7-8-9-10+11+12 = 0
1-2+3-4+5-6-7+8-9+10-11+12 = 0
1-2+3-4+5-6-7-8+9+10+11-12 = 0
1-2+3-4-5+6+7-8-9+10-11+12 = 0
1-2+3-4-5+6-7+8+9-10-11+12 = 0
1-2+3-4-5+6-7+8-9+10+11-12 = 0
1-2+3-4-5-6+7+8+9-10+11-12 = 0
1-2-3+4+5+6-7-8-9-10+11+12 = 0
1-2-3+4+5-6+7-8-9+10-11+12 = 0
1-2-3+4+5-6-7+8+9-10-11+12 = 0
1-2-3+4+5-6-7+8-9+10+11-12 = 0
1-2-3+4-5+6+7-8+9-10-11+12 = 0
1-2-3+4-5+6+7-8-9+10+11-12 = 0
1-2-3+4-5+6-7+8+9-10+11-12 = 0
1-2-3+4-5-6+7+8+9+10-11-12 = 0
1-2-3-4+5+6+7+8-9-10-11+12 = 0
1-2-3-4+5+6+7-8+9-10+11-12 = 0
1-2-3-4+5+6-7+8+9+10-11-12 = 0
1-2-3-4+5-6-7-8-9+10+11+12 = 0
1-2-3-4-5+6-7-8+9-10+11+12 = 0
1-2-3-4-5-6+7+8-9-10+11+12 = 0
1-2-3-4-5-6+7-8+9+10-11+12 = 0
1-2-3-4-5-6-7+8+9+10+11-12 = 0
-1+2+3+4+5+6+7-8-9-10-11+12 = 0
-1+2+3+4+5+6-7+8-9-10+11-12 = 0
-1+2+3+4+5+6-7-8+9+10-11-12 = 0
-1+2+3+4+5-6+7+8-9+10-11-12 = 0
-1+2+3+4-5+6+7+8+9-10-11-12 = 0
-1+2+3+4-5-6+7-8-9-10+11+12 = 0
-1+2+3+4-5-6-7+8-9+10-11+12 = 0
-1+2+3+4-5-6-7-8+9+10+11-12 = 0
-1+2+3-4+5+6-7-8-9-10+11+12 = 0
-1+2+3-4+5-6+7-8-9+10-11+12 = 0
-1+2+3-4+5-6-7+8+9-10-11+12 = 0
-1+2+3-4+5-6-7+8-9+10+11-12 = 0
-1+2+3-4-5+6+7-8+9-10-11+12 = 0
-1+2+3-4-5+6+7-8-9+10+11-12 = 0
-1+2+3-4-5+6-7+8+9-10+11-12 = 0
-1+2+3-4-5-6+7+8+9+10-11-12 = 0
-1+2-3+4+5+6-7-8-9+10-11+12 = 0
-1+2-3+4+5-6+7-8+9-10-11+12 = 0
-1+2-3+4+5-6+7-8-9+10+11-12 = 0
-1+2-3+4+5-6-7+8+9-10+11-12 = 0
-1+2-3+4-5+6+7+8-9-10-11+12 = 0
-1+2-3+4-5+6+7-8+9-10+11-12 = 0
-1+2-3+4-5+6-7+8+9+10-11-12 = 0
-1+2-3+4-5-6-7-8-9+10+11+12 = 0
-1+2-3-4+5+6+7+8-9-10+11-12 = 0
-1+2-3-4+5+6+7-8+9+10-11-12 = 0
-1+2-3-4+5-6-7-8+9-10+11+12 = 0
-1+2-3-4-5+6-7+8-9-10+11+12 = 0
-1+2-3-4-5+6-7-8+9+10-11+12 = 0
-1+2-3-4-5-6+7+8-9+10-11+12 = 0
-1+2-3-4-5-6+7-8+9+10+11-12 = 0
-1-2+3+4+5+6-7-8+9-10-11+12 = 0
-1-2+3+4+5+6-7-8-9+10+11-12 = 0
-1-2+3+4+5-6+7+8-9-10-11+12 = 0
-1-2+3+4+5-6+7-8+9-10+11-12 = 0
-1-2+3+4+5-6-7+8+9+10-11-12 = 0
-1-2+3+4-5+6+7+8-9-10+11-12 = 0
-1-2+3+4-5+6+7-8+9+10-11-12 = 0
-1-2+3+4-5-6-7-8+9-10+11+12 = 0
-1-2+3-4+5+6+7+8-9+10-11-12 = 0
-1-2+3-4+5-6-7+8-9-10+11+12 = 0
-1-2+3-4+5-6-7-8+9+10-11+12 = 0
-1-2+3-4-5+6+7-8-9-10+11+12 = 0
-1-2+3-4-5+6-7+8-9+10-11+12 = 0
-1-2+3-4-5+6-7-8+9+10+11-12 = 0
-1-2+3-4-5-6+7+8+9-10-11+12 = 0
-1-2+3-4-5-6+7+8-9+10+11-12 = 0
-1-2-3+4+5+6+7+8+9-10-11-12 = 0
-1-2-3+4+5-6+7-8-9-10+11+12 = 0
-1-2-3+4+5-6-7+8-9+10-11+12 = 0
-1-2-3+4+5-6-7-8+9+10+11-12 = 0
-1-2-3+4-5+6+7-8-9+10-11+12 = 0
-1-2-3+4-5+6-7+8+9-10-11+12 = 0
-1-2-3+4-5+6-7+8-9+10+11-12 = 0
-1-2-3+4-5-6+7+8+9-10+11-12 = 0
-1-2-3-4+5+6+7-8+9-10-11+12 = 0
-1-2-3-4+5+6+7-8-9+10+11-12 = 0
-1-2-3-4+5+6-7+8+9-10+11-12 = 0
-1-2-3-4+5-6+7+8+9+10-11-12 = 0
-1-2-3-4-5+6-7-8-9+10+11+12 = 0
-1-2-3-4-5-6+7-8+9-10+11+12 = 0
-1-2-3-4-5-6-7+8+9+10-11+12 = 0追问

你是怎么做的?要方法

追答

1+2+3+...+12=78
78÷2=39
只要找到这12个数中哪些相加等于39,把它们前面加上负号,就可以了

追问

恩。谢谢

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