Keebler Foods Co. agreed to buy President Baking Co., maker of Famous Amos and Girl Scout cookies, for $450 million. Keebler, the nation's second-largest cookie maker, said President Baking, the nation's fifth-largest, has annual sales of about $450 million. Atlanta-based President is owned by President International Trading & Investment Inc., which is 61% owned by Taiwan's President Enterprises Corp. Keebler, maker of Cheez-It crackers and Sunshine cookies, has said it would try to purchase other companies to boost its share of the $8.3-billion U.S. cookie and cracker market. The Elmhurst, Ill.-based company said the purchase would add to earnings in 1999 because of cost savings and better use of factories and equipment. Keebler said it would pay for the acquisition with cash and debt. The purchase is expected to be completed in September. Keebler shares rose 13 cents to close at $28.38 on the NYSE.