Inverse Operations

Inverse Operations

What does Inverse Operations mean?

• Inverse means opposite

• When we solve equations using inverse operations we will be using the opposite operation for the symbol we see

• Addition and Subtraction are opposites

• Multiplication and Division are opposites

Why do we use inverse operations?

• We use inverse operations to solve for variables

• Variables are the letters that you see in math equations

• Ex: x+2=7

• We use inverse operations to undo problems in order to find what x is equal to.

Now let's try solving an equation together

• b-4=12

• Our first step is to get b on a side completely by itself.

• That means we have to find a way to get rid of the 4.

• We have to do the opposite of subtracting 4.

Multiple Choice

What is the opposite (inverse) of subtracting 4?

b-4=12

• Adding 4

• Multiplying by 4

• Dividing by 4

Great job!

When solving b-4=12 we have to add 4 to both sides. When you add +4 and -4 you get 0. This means that the -4 is now cancelled out and b is on a side by itself. Your problem should now look like this:

b-4=12

+4 +4

b=16

Breaking it down

• We added 4 to both sides in b-4=12 because when working with inverse operations the rule is: WHATEVER YOU DO TO ONE SIDE OF THE EQUAL SIGN YOU HAVE TO DO TO THE OTHER.

• Since we added 4 on the left side of the equal sign, we also needed to add 4 to 12 on the right side.

• You wind up with b=16 because 12+4=16.

• The picture on this slide shows another example of whatever you do to one side, you must do to the other.

Multiple Select

Does this make sense so far?

• Yes

• No

• Kind of

Okay let's try some more practice problems

Multiple Choice

3+x=19

What is the first step?

• Add 3 to both sides

• Subtract 3 from both sides

• Multiply by 3 on both sides

• Divide by 3 on both sides

Multiple Choice

Correct you subtract 3 from both sides!

Your problem should now say

x=19.

Are there anymore steps?

• Yes

• No

Multiple Choice

What is the correct answer to this equation?

t-13=27

• t=40

• t=14

• t=-13

• t=27

Very good guys!

Now that you've had some practice, let's give this worksheet a try :)

Multiple Choice

3+x=19

What is the first step?

• Add 3 to both sides

• Subtract 3 from both sides

• Multiply by 3 on both sides

• Divide by 3 on both sides