NUMBER SYSTEMS
Integers
Whole Numbers are enough for counting, but let's try something different.
Subtracting 2 from 1 means moving 2 steps backward from 1.
We end up at −1.
But −1 is not a Whole Number.
So Whole Numbers are not enough to describe every result of subtraction.
KEY IDEA
We need numbers that extend below zero.
These numbers are called Integers.
Integers include negative numbers, zero, and positive numbers.
NEXT LIMIT
Integers allow us to handle subtraction like 1 − 2.