power 4dPick your 4D Powerball numbers 3 ways to increase your chances to win: add more 4D numbers, Powerballs, or both to form more combinations. Just add RM2 for every possible Powerball combination you get from your Combo Play. ORA convex lens of power + 6D is placed in contact with a concave lens of power – 4D. What is the nature and focal length of the combination. see full answer. Start JEE NEET Foundation