‘UNDOING’ A SEQUENCE OF OPERATIONS
LESSON READ-THROUGH
by Dr. Carol JVF Burns (website creator)
Follow along with the highlighted text while you listen!
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In this exercise, you will practice ‘undoing’ operations.

The expression $\,2x + 1\,$ represents the sequence of operations:
start with a number $\,x\,$, multiply by $\,2\,$, then add $\,1\,$.

To ‘undo’ these operations and get back to $\,x\,$, we must apply the sequence:
subtract $\,1\,$, then divide by $\,2\,$.

Start with $\,x\,$ and follow the arrows in the diagram below.
This shows you doing something, and then undoing it, to return to $\,x\,$!

$x$ $\overset{\text{multiply by 2}}{\rightarrow}$ $2x$ $\overset{\text{add 1}}{\rightarrow}$ $2x + 1$
        $\,\downarrow\,$
$x$ $\overset{\text{divide by 2}}{\leftarrow}$ $2x$ $\overset{\text{subtract 1}}{\leftarrow}$ $2x + 1$

Remember some key ideas:

Master the ideas from this section
by practicing the exercise at the bottom of this page.


When you're done practicing, move on to:
Solving for a Particular Variable

 
 
CONCEPT QUESTIONS EXERCISE:
On this exercise, you will not key in your answer.
However, you can check to see if your answer is correct.
PROBLEM TYPES:
1 2 3 4 5 6 7 8
AVAILABLE MASTERED IN PROGRESS

Write the sequence of operations needed to get back to the number $\,x\,$:
(MAX is 8; there are 8 different problem types.)