Abstract: Methods of portioning by weight a plurality of articles of randomly varying weight. An array of articles is randomly assembled and then individual weights sensed. Some of these articles are then selected, to add up to the desired total weight. A preliminary step can be used wherein articles of unknown weight are first assembled to form a preliminary weight portion known to be short of the desired final weight, and then articles of known weight are added to reach the final target weight. An apparatus for accomplishing the methods comprises an array of scales dischargable upon signal from a control system, means for resupplying the scales, and a control system for sensing, storing and analyzing the weights of articles in the scales, and causing the proper scales to be discharged.