DrDelMath

Elementary Algebra at Meramec

SUMMARY
Chapter 1:  Introduction to Algebra

Section 1.1: Introduction to the Language of Algebra

Goals-- What You Should Learn

1. Goal One
2. Goal Two
3. Goal Three

Links to Supplemental Material
Always Check the List of OnLine Drill and Practice

 















Section 1.2: Fractions

Goals-- What You Should Learn

1. Goal One
2. Goal Two
3. Goal Three

Links to Supplemental Material
Always Check the List of OnLine Drill and Practice

 



























Division of fractions is exactly like all divisions in mathematics


Because the multiplicative inverse of a fraction is its reciprocal, the conversion to multiplication looks like:


After converting to multiplication and performing the multiplication according to the definition of multiplication we get the following rule.


All of this boils down to a fairly simple rule for working with division of fractions as set forth in the following definition.








Subtraction of fractions is exactly like all subtractions in mathematics


Using one of the four forms for the opposite of a fraction makes the conversion to addition look like:


From which we get the following definition of subtraction for fractions.







 

Section 1.3: The Real Numbers

Goals-- What You Should Learn

1. Goal One
2. Goal Two
3. Goal Three

Links to Supplemental Material
Always Check the List of OnLine Drill and Practice

 













 

Section 1.4: Adding Real Numbers

Goals-- What You Should Learn

1. Goal One
2. Goal Two
3. Goal Three

Links to Supplemental Material
Always Check the List of OnLine Drill and Practice

 

With advanced mathematics, it can be proven that the points on an infinitely long line are in one-to-one correspondence with the real numbers. Remember the real numbers include rationals, irrationals, integers, whole numbers, and natural numbers. To say there is a one-to-one correspondence between the points of the line and the real numbers means that:
(i) for every real number there corresponds exactly one point on the line
(ii) for every point on the line there corresponds exactly one real number.

This give rise to the concept of "The Number Line" which is a geometric way of visualizing the real numbers.
It is common to draw the number line showing only the integer points. When that is the case it is your responsibility to recognize that all the rational numbers and all the irrational numbers are represented on that same line.

It is imperative that you observe the order of the real numbers as displayed by the number line.
At any point on the number line, the numbers increase to the right and decrease to the left.

This leads to a natural interpretation and visualization for addition of signed numbers. Now note that adding a positive number (to any number) means to increase and thus means move right. On the other hand, adding a negative number (to any number) means to to decrease and thus means move left. This visualization will always yield the correct sign for the sum.

  

On the number line the symbol < (read as "less than") means "to the left of".
On the number line the symbol > (read as "greater than") means "to the right of".

Section 1.5: Subtracting Real Numbers

Goals-- What You Should Learn

1. Goal One
2. Goal Two
3. Goal Three

Links to Supplemental Material
Always Check the List of OnLine Drill and Practice

 



Section 1.6: Multiplying and Dividing Real Numbers

Goals-- What You Should Learn

1. Goal One
2. Goal Two
3. Goal Three

Links to Supplemental Material
Always Check the List of OnLine Drill and Practice

 

 

The product of two real numbers with the same signs is positive.
The product of two real numbers with different signs is negative.



Section 1.7: Exponents and Order of Operations

Goals-- What You Should Learn

1. Goal One
2. Goal Two
3. Goal Three

Links to Supplemental Material
Always Check the List of OnLine Drill and Practice

 

















Section 1.8: Algebraic Expressions

Goals-- What You Should Learn

1. Goal One
2. Goal Two
3. Goal Three

Links to Supplemental Material
Always Check the List of OnLine Drill and Practice