 Hello and welcome to this session. I am Ashima and I am there to help you with the following problem. Find the sum of the following AP that is minus 37, minus 33, minus 29, so on to 12 terms. Now before writing the solution let us look at the key idea. Here sn is equal to n by 2 multiplied by 2a plus n minus 1 multiplied by d. Here sn is the sum of the AP, a is the first term, d is the common difference and n is the number of terms. Now let us write the solution. Given AP is minus 37, minus 33, minus 29, so on to 12 terms. Here a is equal to minus 37, d is equal to common difference of this so minus 33 minus of minus 37. Which is equal to minus 33 plus 37 which is equal to 4 and n is equal to 12. So applying the formula sn is equal to n by 2 multiplied by 2a plus n minus 1d which is equal to n is 12. 12 by 2 multiplied by 2 into a is 2 multiplied by minus 37 plus 12 minus 1 multiplied by d that is 4. Now this gets cancelled by 6 so 6 multiplied by minus 74 plus 11 into 4 which is equal to 6 multiplied by minus 74 plus 44. Which is equal to 6 multiplied by minus 30 which is equal to minus 180 so sn is equal to minus 180 therefore the required sum is minus 180. I hope you understood the problem bye and have a nice day.