The classic way to convey the error that exists in a measurement is a formula that shows the obtained measurement (X) as a sum of a true score plus some error. One version of this formula is: X = T + e. With this formula in mind, obtaining more precise measures depends on reducing error.
  Mega is the prefix meaning one million, therefore there are one million (1,000,000) gallons in a mega gallon.
To find the amount of gallons that are in a ton of water, it is important to note how many pounds are in a gallon. Since there are 8.33 pounds in a gallon, and there are 2,000 pounds in a ton, the equation is as simple as dividing the 2,000 pounds by 8.33 pounds.