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So all 2 digit natural numbers is

10 + 11 + ... + 99

so s = n(n+1)/2 - 45

s = 99 x 100/2 - 45

s = 4950 - 45 = 4905__ANSWER__

10 + 11 + ... + 99

so s = n(n+1)/2 - 45

s = 99 x 100/2 - 45

s = 4950 - 45 = 4905

Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.

Sum of 'n' numbers is

2nd method:

Sn = n/2 [a+l]

Sn = 45(109)

Sn = 4905