Question: what is the number of basic units in the international system of units?
Answer: seven

The International System of Units ( SI ) defines seven units of measure as a basic set from which all other SI units can be derived . The SI base units and their physical quantities are the metre for measurement of length , the kilogram for mass , the second for time , the ampere for electric current , the kelvin for temperature , the candela for luminous intensity , and the mole for amount of substance .