power 4dWin a 4D lottery winning numbers has never been easier and is not based on luck. It's all about math, manipulation, statistic and hardworking study on how to win. Our 4D predictionA 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