Warm Up

A. The Evolution of Numbers

Children are introduced to numbers, one subset at a time.

The very first subset that children are introduced to is the counting numbers, starting with the number one. Perhaps since counting is so natural, the first subset is called the Natural Numbers.

N = {1, 2, 3, ...}

Natural Numbers
the counting numbers; N = {1, 2, 3, ...}

 

The Whole Numbers include the Natural Numbers and the number 0. The need to represent a quantity of zero, or nothing, is satisfied by this subset.

W = {0, 1, 2, 3, ...}


Whole Numbers
the Natural Numbers and zero; W = {0, 1, 2, 3, ...}

 

Integers comprise the positive and negative counting numbers and zero, just as you would find on a Celsius thermometer. The Whole Numbers and Natural Numbers subsets are included in the Integers subset.

Both Z and I are used to represent Integers.

Z = {..., −3, −2, −1, 0, 1, 2, 3, ...}


Integers
the Natural Numbers, their negatives, and zero; Z = {..., −3, −2, −1, 0, 1, 2, 3, ...}