How was the 4,500 shares outstanding calaculated, because it was not provided in the question?

Pine Corporation has the following accounts at December 31: Common Stock, \$10 par, 5,000 shares issued, \$50,000; Paid-in Capital in Excess of Par-Common Stock \$30,000; Retained Earnings \$45,000; and Treasury Stock, 500 shares, $11,000. Prepare the stockholders' equity section of the balance sheet