qqp question1: How does one calculate [math]\frac{1}{1 \times 2} [/math] + [math]\frac{1}{3 \times 4}[/math] + … ? question2: How would you calculate [math]\sum_{n=1}^\infty \frac{1}{2^n} \cdot \frac{1}{n - \frac45}[/math]?