1.In A Shallow Bowl, Mix The Flour, Salt, And Pepper. Lightly Coat The Round Steak Pieces In The Flour Mixture. 2.Heat The Oil In A Skillet Over Medium Heat, And Saute The Celery, Onion, And Carrots About 5 Minutes, Until Tender. Remove From Heat, And Set Aside. Mix In The Round Steak Pieces, And Cook Until Lightly Browned. 3.Place The Vegetables And Steak In A Slow Cooker. Mix In The Tomatoes With Juice, Worcestershire Sauce, And Brown Sugar. 4.Cover, And Cook 8 To 10 Hours On Low, Until The Round Steak Is Very Tender.