Question 19Evaluate $\frac1{1\cdot2}+\frac5{2\cdot3}+\frac{11}{3\cdot4}+\cdots+\frac{71}{8\cdot9}+\frac{89}{9\cdot10}$.$\frac{81}{10}$$\frac{89}{10}$$9$$\frac{91}9$None of the above