COUNTING PRINCIPLES
According to Gelman & Gallistel (1978) The one-one principle: There is a distinct counting word to match each of the items counted. The stable-order principle: The list of words must be consistent. The cardinal principle: The final word tells us how many there are in the number of items counted. The abstraction principle: You can count any collection of objects whether real or imaginary. The order irrelevance principle: It doesn’t matter what order you count in as long as you count each object only once you will get the same result.