[tex] \frac{1}{201} + \frac{2}{201} + ... + \frac{201}{201} [/tex]
[tex] = \frac{1 + 2 + ... + 201}{201} = \frac{ \frac{201(201 + 1)}{2} }{201} = \frac{ \frac{201 \times 202}{2} }{201} [/tex]
[tex] = \frac{201 \times 101}{201} = 101[/tex]
[tex]formula \: : \: 1 + 2 + ... + n = \frac{n(n + 1)}{2} [/tex]
