The odd natural numbers are an arithmetic sequence with d = 2 and [math]a_1=1[/math]. The 50th odd number is [math]a_{50} = a_1 + (n - 1)d = 1 + (50–1) \cdot 2 = 99[/math]. read more
we can find the sum of first 50 odd numbers with the formula for the sum of n numbers in arithmetic progression. Sn=n(a+l)/2, where sn= sum of n numbers, a= 1st number of the series. l= last number of the series. read more