87
Wiki User
∙ 2011-07-18 10:36:4081*82/2= 3321
2
2
if (n%2==0) sum=n/2*(n+1); else sum=(n+1)/2*n;
Sum = 79*(79+1)/2 = 79*80/2 = 3160
1+2+4 = 7
The sum of the numbers given is 31. 1 + 2 + 4 + 8 + ... + 2n = 2n+1 - 1
3
They are: 79+2 = 81
You add 1 plus another one and you get 2
The sum of -1 and -1 is -2.
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