Gauss Again
Answer Page
Question
Answer
sum of pairs
11
sum of 1-10
55
sum of pairs
101
sum of 1-100
5050
formula
(n/2)(n+1)
other method
50(100)+50
sum of 1-50
(50/2)(51)=25(51)=1275
sum of 1-99
(99/2)(100)=4950
sum of evens 2-200
2(5050)=10100
