How many calories should I eat to gain 0.5 pounds of muscle a week I'm 73 pounds and 4 foot 5 at 13

Probably about 1800 if your working out consistently (about 3 times a week) also you don’t have to ask this here you can go to your browser and look up a calorie calculator it can give you the amount of calories needed to gain/ lose weight and some can give you your macros as well

From a high concentration to a low concentration.