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The sum of all the two-digit odd numbers is
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The correct answer is:
2475
Sum of odd numbers $=\mathrm{n}^{2}$
Two-digit odd numbers are from $11-99$.
Number of odd numbers from 1 to $99=50$
Sum of odd numbers from 1 to $99=50^{2}=2500$
Number of odd numbers from $1+9=5$
Sum of odd numbers from 1 to $9=5^{2}=25$
So, Sum of all two digit odd numbers
$=2500-25=2475 .$
Two-digit odd numbers are from $11-99$.
Number of odd numbers from 1 to $99=50$
Sum of odd numbers from 1 to $99=50^{2}=2500$
Number of odd numbers from $1+9=5$
Sum of odd numbers from 1 to $9=5^{2}=25$
So, Sum of all two digit odd numbers
$=2500-25=2475 .$
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