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Chameleon Graphing

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Negative Numbers on a Line

So far, when Sam wanted to graph a point, he started at zero and went forward. What would happen if he wanted to go the other way? After all, there are lots of points before the one we labelled zero.

Let's label some more points, going backwards from zero. We'll use the "-" symbol to show that these numbers are less than zero.

<---(-3)---(-2)---(-1)---0---1---2--->

The numbers before zero on the number line are called negative numbers. We read a number like -4 as "negative four."

Let's ask Sam to graph negative two.

    Sam always starts at zero.

    <---(-3)---(-2)---(-1)---Sam---1---2--->

    Sam knows he has to graph a negative number, so he turns around.

    <---(-3)---(-2)---(-1)---maS---1---2--->

    He moves two units away from zero, because negative two is two less than zero.

    <---(-3)---maS---(-1)---0---1---2--->

    Finally, Sam marks the point he found with a big green dot.

    <---(-3)---*---(-1)---0---1---2--->

Sam found -2.

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