Question

Calculate sum and average of the first 100 natural numbers using for

Answer 1

sum=n÷2{2a+(n-1)×d}
=100÷2{2×1+(100-1)×1}
=50(2+99)
=50×101
=5050
or
n(n+1)÷2
100(100+1)÷2
10100÷2
= 5050

average=sum÷n
5050÷100
50.5