Without adding, find the sum

(i) 1 + 3 + 5 + 7 + 9

(ii) 1 + 3 + 5 + 7 + 9 + I1 + 13 + 15 + 17 +19

(iii) 1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17 + 19 + 21 + 23

(i) As per the question, we have to find the sum of first five odd natural numbers.

Therefore,

1 + 3 + 5 + 7 + 9

= (5)^{2}

= 25

(ii) As per the question, we have to find the sum of first ten odd natural numbers

Therefore,

1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17 + 19

= (10)^{2}

= 100

(iii) As per the question, we have to calculate the sum of first twelve odd natural numbers

Therefore,

1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 +17 + 19 + 21 + 23

= (12)^{2}

= 144

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