How do I calculate the exponential smoothing need explanation manually and answers ?? no Excel thanks

View Policies Current Attempt in Progress The following data are monthly sales of jeans at a local department store. The buyer would like to forecast sales of jeans for the next month, July. Month Sales January 39 February March April May 51 June 33 43 39 Forecast sales of jeans for Merch through June using the naive method, a two-period moving average, and exponential smoothing with an a=0.1. (Round answers to 1 decimal place, e.g. 15.2.) 2-Period Moving Exponential Month Sales Nalve Forecast Average Smoothing January 39 February 33 March 43 33 36 April 39 43. 38 May 51 39 41 June 44 51 45