Find the sum 1 + 3 + 5 + … + 51 (the sum of all odd numbers from 1 to 51) without actually adding them.
Here, the quotient obtained upon dividing 51 by 2 is 25.
∴Number of terms = n = 25 + 1 = 26
∴ 1 + 3 + 5 + … + 51 = 262 = 676
Without doing te actual addition, find the sum of :
(i) 1+3+5+7+9+11+13+15+17+19+21+23
(ii) 1+3+5+7+9+....... +39+41
(iii) 1+3+5+7+9+........+51+53