Accompanying Resource:
Classifying Real Numbers Boom Cards 
Did you know that numbers haven't been around forever? Way back when, people didn't have words or symbols for numbers as simple as 1, 2, 3. . . Before numbers and their symbols were invented, people used sticks and made tally marks on stones as ways to keep track of things. Thankfully, a number system developed over time so we no longer need to use sticks or hold up fingers to count! We now have names and symbols that we use to represent numbers. (Want to see some of the earlier symbols that were used? Check out this article on the history of the number system.)

Here's a diagram to help you understand how all of the different types of numbers are related to each other. The natural numbers are inside of the whole numbers because all natural numbers are also whole numbers. Whole numbers are inside of the integers because all whole numbers are also integers. Integers are inside of the rational numbers because all integers can be written as a fraction.
