Question

Express $81$ as the sum of the first nine consecutive odd numbers.

Answer 1

Express the given number as the sum of the first nine consecutive odd numbers:

The whole numbers, which can not be divided by $2$, are known as odd numbers.

Thus, the first nine consecutive odd numbers are $1,3,5,7,9,11,13,15$ and $17$.

Now, the given number is $81$.

It can be expressed as,

$81=1+3+5+7+9+11+13+15+17$.

Hence, the given number can be expressed as $\mathbf{81}\mathbf{=}\mathbf{1}\mathbf{+}\mathbf{3}\mathbf{+}\mathbf{5}\mathbf{+}\mathbf{7}\mathbf{+}\mathbf{9}\mathbf{+}\mathbf{11}\mathbf{+}\mathbf{13}\mathbf{+}\mathbf{15}\mathbf{+}\mathbf{17}$.