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Without adding, find the sum. (i) 1+3+5+...

Without adding, find the sum. (i) `1+3+5+7+9` (ii) `1+3+5+7+9+l1+13+15+17+19`

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Sum of `n` cosecutive odd numbers `=n^2`
(i) `1+3+5+7+9`
Here, `n=5`
Therefore, `1+3+5+7+9=5^2=25`
(ii) `1+3+5+7+9+11+13+15+17+19`
Here, `n=10`
Therefore, `1+3+5+7+9+11+13+15+17+19=10^2=100`
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