Length, Mass, Quantity, Temperature, Time. The other quantities are based on them or derived from them.
Base quantities have a base unit and a reference standard.
1 m Relationships between the Kelvin, Celsius, and Fahrenheit scales of temperature. When adding or subtracting measurements you should first calculate the answer using all digits available. The result is allowed to have no more decimal places than are in the number having the fewest decimal places . In multiplication or division of measured quantities you should first perform all of the calculations involved. Then determine how many significant digits are in each of the quantities used in the calculations.