Question

Square and Square roots:Write 81 as the sum of consecutive odd numbers.

Answer 1

Question

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

Answer:

81 as the sum of first 9 consecutive odd numbers is 7+9+11+13+15+17.

1+3+5+7+9+11+13+15+17 = 81  

Here, LHS = RHS ..

Answer 2

Answer:

81 is the sum of first 9 odd digit natural numbers,

i.e,

1+3+5+7+9+11+13+15+17 ,

= (9/2)[1+17],

= (9/2)*18,

= 81.