Dave Ryan is the CEO of Ryan's Arcade. At the end of its accounting period, December 31, Ryan's Arcade has assets of $644,560 and liabilities of $236,380. Using the accounting equation, determine the following amounts:

a) Stockholders' equity as of December 31 of the current year. $

b) Stockholders' equity as of December 31 at the end of the next year, assuming that assets increased by $81,440 and liabilities increased by $18,750 during the year. $