# Substituting with Negative Numbers

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Substituting negative numbers into expressions is the same as substituting positive numbers, except that we need to know the “Integers Rules”.

“Integers” is the mathematical word that refers to positive and negative numbers.

The main Integers Rules we need to remember are the ones for Multiplying, Dividing, and Subtracting.

Integers Revision

For Multiplying integers, we use the following set of rules.

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If you need to review Multiplying Integers, then click the following link:

http://passyworldofmathematics.com/multiplying-integers/

The rules for Dividing Integers are the same as for multiplying positives and negatives.

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If you need to review Dividing Integers, then click the following link:

http://passyworldofmathematics.com/dividing-integers/

For Subtracting Integers, we Add the Opposite.

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Subtraction can also be done using the “Keep Flip Change” rule.

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If you need to review Subtracting Integers, then click the following link:

http://passyworldofmathematics.com/subtracting-integers/

Here is a video that involves substituting negative and positive values.

This next video shows how to substitute when brackets are in the question.

Substituting Negatives Examples

Image Copyright 2012 by Passy’s World

Image Copyright 2012 by Passy’s World

Image Copyright 2012 by Passy’s World

Image Copyright 2012 by Passy’s World

Values Tables Substitution

We sometimes need to use a supplied rule equation to complete a values table of “x” and “y” values.

These tables are used when we need to draw a graph for the rule. However we will not be drawing the graph in this example.

If you want to see an example where we make the graph from the completed values table, then click the lesson link below:

http://passyworldofmathematics.com/plotting-graphs-from-t-tables/

This next example is basically four separate substitution questions, where we are putting our four answers into an answer table.

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We now need to work out “y” answers for the other three “x” values the same way.

At Passy’s World we find it easiest to do these questions by adding a middle column to the table where we do the working out.

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