Explicație pas cu pas:
[tex]\frac{1}{1 \times 3} + \frac{1}{3 \times 5} + \frac{1}{5 \times 7} + ... + \frac{1}{97 \times 99} = \\ \frac{1}{1} - \frac{1}{3} + \frac{1}{3} - \frac{1}{5} + ... - \frac{1}{97} + \frac{1}{99} = \\ \frac{1}{1} + \frac{1}{99} = \frac{100}{99} [/tex]