Find the number of baseball ordered in December 2017.
Product Name = 'Baseball'; December 2017 refers to OrderDate LIKE '12/%/17';
SELECT COUNT(T2.OrderNumber) FROM Products AS T1 INNER JOIN `Sales Orders` AS T2 ON T2._ProductID = T1.ProductID WHERE T1.`Product Name` = 'Baseball' AND T2.OrderDate LIKE '12/%/18'