(n2 + n)/2
1+2+3+4+5+n=
15+n
Wiki User
∙ 2009-12-31 00:29:131+2+3+4.....+100 = 101*50= 5050
The sum of 2/3 and 1/2 is 1 1/6
The sum of 5/12 and 2/3 is 1 1/12The sum of 5/12 and 2/3 is 1 1/12
500,000,500,000 is the answer.
The sum of 2/3 and 5/6 is 1 1/2.
3
3
Sum = 79*(79+1)/2 = 79*80/2 = 3160
25
5050
87
if (n%2==0) sum=n/2*(n+1); else sum=(n+1)/2*n;
41
The sum of -1 and -2 is -3.
The sum of 2/9 and 1/3 is 5/9
1+2+3+4.....+100 = 101*50= 5050
81*82/2= 3321