The Associative Laws say that it doesn't matter how we group the numbers (i.e. which we calculate first) ... ... when we add : (a + b) + c = a + (b + c). ... or when we multiply : (a Ã b) Ã c = a Ã (b Ã c).
To complete the PCT in two months (or less) you will need to average approximately 43.6 mi / 70.2 km per day (this was my longest day on trail).
Practice vision therapy in a supervised setting for the required amount of time. Certification for optometry technicians typically requires several hundred supervised practice hours. Certification for a practicing optometrist requires three years of overall practice with two years devoted to vision therapy.