1. Preheat oven to 350°F.
2. Place the sliced apples in a 9-x13-in. pan. Mix the 1/4 c. brown sugar, 1 Tbsp. flour and ground cinnamon together and sprinkle over apples.
3. In a bowl, combine the 1-1/2 c. flour, oatmeal, 1 c. brown sugar, baking soda and salt. Cut in the margarine until mixture is crumbly. Spread evenly over the apple mixture. Bake for about 45 min.