Question

Without adding find the sum of first 12 odd numbers

Answer 1

We can find through A.P formula

Sum of first 'n' odd numbers=n²

∴sum of first 12 odd numbers=12²=144

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Answer 2

1,3,5 ........23.
a = 1 , d = 3-1 = 2 , n = 12
Sum = 12/2 [2 X 1 + (12-1)2]
= 6[2 + (11)2]
= 6(2 + 22)
= 6 X 24
= 144
144 is the correct answer