In order to find the average of all the costs, first you need to add up all of the expenditures from each month. (ex. 1,084.45+886.40+968.45+1,117.60+995.80+1,379.86) After you find the solution from adding those numbers together, divide the solution by the amount of costs there are in order to find the average. Since it was for 6 months, get the total from the addition problem and divide it by 6 and that will be your answer.