Find the sum of all odd numbers between

(i) 0 and 50


(ii) 100 and 200

(i) 0 and 50


a = 1, l = 49, n = 25


S25= [a + l]


= [1 + 49]


= (50) = 625


(ii) 100 and 200


a = 101, l = 199, n = 50


S50= [a + l]


= 25 (101 + 199)


= 25 (300) = 7500


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