 Welcome to the session. I am Asha and I am going to help you with the following question which says find the sum of odd integers from 1 to 2001. So, let us begin with the solution and we have to find the sum of all the odd integers from 1 to 2001. So, we have to find 1 plus 3 plus 5 plus 7 plus 9 plus 4 up to 2001. The last term is 2001 of this series, last term or the nth term is equal to a plus n minus 1 into d is equal to 2001 where first term of this sequence is the number of terms and d is the common difference. In the series we find that here the first term a is equal to 1, common difference d is equal to 2, we have to find n, now since a plus n minus 1 into d is equal to 2001, so on substituting the values of a and d we have 1 plus n minus 1 into 2 is equal to 2001, that is n minus 1 into 2 is equal to 2001 minus 1, so we have n minus 1 into 2 is equal to 2000 or n minus 1 is equal to 1000 or we can say that n is equal to 1000 plus 1 is equal to 1001 to find the sum of the terms. So, in all we have 1001 terms from 1 to 2001 and sum of n terms is given by n upon 2 to a plus n minus 1 into d, so sum will be equal to n is 1001 upon 2 2 plus again 1001 minus 1 into d is 2, this is further equal to 1001 upon 2 into 2 plus 1000 into 2 which is further equal to 1001 upon 2 to 2 plus 2000 which is further equal to 1001 upon 2 into 2002, now 2002, so we have 1001 into 1001 which is equal to 1002 001, hence the sum of all the ordent teachers from 1 to 2001 is 1002 001, so this completes the session, hope you enjoyed it, take care and have a good day.