In ArcGIS I have a 3 Landsat NDVI datasets for 3 consecutive months and would like to calculate the mean bare soil (in hectares) for which I have manually worked out to be between the values of 105 and 126 for my AOI.

I have tried using the raster calculator, however when I go back to validate the results for say value 105, the count values across the 3 datasets are 5,40 and 35 respectively, shouldn't the mean count be 26.6 (5+40+35/3)? However in the output dataset, I get a count value of 2.

What are I doing wrong or maybe I have missed a step in ArcGIS?

[![enter image description here](https://i.stack.imgur.com/TQIOi.jpg)](https://i.stack.imgur.com/TQIOi.jpg)