Question 21
The value of $\frac1{1\times3}+\frac1{3\times5}+\frac1{5\times7}+\frac1{7\times9}$ is $\frac mn$. Find $m+n$.
Write m/n in lowest terms, with m and n positive integers. The source omits the lowest-terms condition.
Write m/n in lowest terms, with m and n positive integers. The source omits the lowest-terms condition.