Rhubarb Crunch

3 c. diced rhubarb
1 c. white sugar
3 Tbsp. all-purpose flour
1 c. packed light brown sugar
1 c. quick-cooking oats
1 1/2 c. all-purpose flour
1 c. butter

Preheat oven to 375°. Lightly grease a 9-inch by 13-inch baking dish. In a large mixing bowl, combine rhubarb, white sugar and three tablespoons flour. Stir well and spread evenly into baking dish. Set aside. In a large mixing bowl, combine brown sugar, oats and 1 1/2 cups flour. Stir well, then cut in butter or margarine until mixture is crumbly. Sprinkle mixture over rhubarb layer. Bake in preheated oven for 40 minutes. Serve hot or cold.