Microwave Marshmallow Crispy Treats

1/4 cup margarine
40 regular marshmallows or 6 cups mini-mallows
6 cups Rice Krispies

Microwave margarine in a large bowl on high for 45 seconds. Add marshmallows; toss to coat. Microwave 1 1/2 minutes or until smooth. Stir after 45 seconds. Add cereal and toss. Press into buttered 9 X 13 pan.