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.
The US gallon is legally defined as 231 cubic inches, which is exactly 7000378541178400000â 3.785411784 liters. A US liquid gallon of water weighs about 8.34 pounds or 3.78 kilograms at 62 Â°F (17 Â°C), making it about 16.6% lighter than the imperial gallon. There are four quarts in a gallon, two pints in a quart and 16 US fluid ounces in a US pint, which makes the US fluid ounce equal to 1â128 of a US gallon.