Critical Hit double dice value

Double the value shown on your dice for a critical hit – 2d6 + 3 becomes {2d6 x 2} + 3. This is to speed along the game by simplifying the amount of math and dice rolled. (RAW you roll twice as many dice, so 2d6 + 3 becomes 4d6 + 3 on a critical hit. PHB page 196.)