100+99+98+97+96+...=? Formula?

100+99...+1

in a shorter form:

4+3+2+1=10

4+1=5, 3+2=5

Largest/2 = 4/2 = 2

2+3=5

5*2=10

so:

100/2 = 50

50+51=101

101*50=5,050

Answer=5,050

((Largest/2)+((Largest/2)+1)) * (Largest/2)

This works for Largest when even and Smallest when 1

Formula=[Last term X Last term+1] / 2

Formula =[100 X 101]/2 =5,050.