What is the average of 1200 755 -450 210 -640 over 5 months?

To find the average of the numbers 1200, 755, -450, 210, and -640, first sum them: 1200 + 755 - 450 + 210 - 640 = 1075. Then, divide the total by 5 (the number of months): 1075 / 5 = 215. Thus, the average over 5 months is 215.