Question 13
The sum
$$\frac1{1\cdot2\cdot3}+\frac1{2\cdot3\cdot4}+\frac1{3\cdot4\cdot5}+\cdots+\frac1{100\cdot101\cdot102}$$
is $a/b$ in lowest terms. Find $a+b$.
$$\frac1{1\cdot2\cdot3}+\frac1{2\cdot3\cdot4}+\frac1{3\cdot4\cdot5}+\cdots+\frac1{100\cdot101\cdot102}$$
is $a/b$ in lowest terms. Find $a+b$.