Computing Weighted-Average Common Shares

On January 1, 2020, Case Inc., had 960,000 shares of common stock issued and outstanding. Case issued a 10% stock dividend on July 1, 2020. On October 1, 2020, Case purchased 76,800 shares of its common stock for the treasury. What is the number of shares that should be used in computing basic earnings per share for the year ended December 31, 2020?

The answer is 1,036,800 for weighted-average common sahres outstanding but I do not know how they got this number!