Question

Express $121$ as the sum of $11$ odd numbers.

Answer 1

Express $121$as the sum of $11$ odd numbers

The formula for the sum of first $n$odd numbers is

$S_{odd}=n^2$

where, $S_{odd}$ is the sum of the first $n$ odd numbers

$$\begin{gathered} \Rightarrow n^2=121 \\ \Rightarrow n=11 \end{gathered}$$

Therefore, $121=1+3+5+7+9+11+13+15+17+19+21$