Q2 of 69 Page 72

Find the sum of first 123 even natural numbers.

List of first 123 even natural number is

2,4,6,…….


Where first term a = 2


Second term t1 = 4


Third term t2 = 6


Thus, common difference d = t2 – t1 = 6 – 4 = 2


n = 123


By using sum of nth term of an A.P. is



Where, n = no. of terms


a = first term


d = common difference


Sn = sum of n terms


Thus, Substituting given value in formula we can find the value of Sn






Thus, Sn = 15252


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