Appetizers and Lessons for Mathematics and Reason (www.whyslopes.com)
||Définition d'une variable || Algèbre || Arithmetique || Logique ||La raison basée sur les règles et modelés||

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1,  Elements of Reason.
1A. Pattern Based Reason 
1B. Math Curriculum Notes
2. Three Skills for Algebra
3. Why Slopes & More Math

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1. Help Your Child or Teen Learn 
2. Solving Linear Equations
3. Fractions Ratios Rates Proportions & Units
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YOU are better than YOU think. Show yourself  how:  

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Read  logic chapters 1 to 5  in online volume Three Skills for Algebra  for greater skills & confidence in  work 
and study

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 Logic chapters 1 to 5  re- appear not in sequence, as is or longer,  in  Volume 1A,  Pattern Based Reason, Bon Appetite.

Logic Mastery
 Amazing, Amusing, Amorous,  Delicious, Delightful, Edifying, Strengthening Elixir. 
It eases work & learning difficulties Makes the hard easier. Opens eyes. Leads to greater precision.
in reading and
writing

Logic mastery makes the hard, easier. Logic mastery  leads to better, stronger and richer comprehension.  Logic mastery  improves reading and writing.  Logic mastery ease learning difficulties.  Logic mastery gives a headstart.  In sum, logic mastery  will develops critical thinking, improve reading and writing, and give a firmer base for work and studies at many levels. Good luck.


After logic  (a) continue reading Three Skills for Algebra, chapters 8 to 14  and do so alongside site area on solving liinear Equations ; or (b) see this calculus starter lesson and Volume 3, Why Slopes  & More Math, chapters 2 to 6;

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Caution: Site advice is approximately correct, for some circumstances, not all. That leaves room for thought

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What may be learnt and when depends on how skills and concepts are developed. Making the hard easier and clearer will allow earlier & richer development of skills and concepts.


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For online automated help in senior high school maths & calculus, visit  quickmath.com  For Automatic Calculus and Algebra Help with derivatives, integrals, graphs, linear equations, matrix algebra, visit calc101.com  With  overlap, each site quickmath & calc101offers a different range of services, some free, some not, all based on webmathematica. Good luck.

Calculations with Simple and Compound Units

Mastery of formal operation with expression involving units is needed for proportionality computations or relationships between quantities or between numbers and quantities. We  do operations on (formal) expressions without requiring those expression have any meaning or physical interpretation.  That provide on paper exercises with marks or expression on paper.  In a following section on proportionality, multiples of simple and compound units will serve as proportionality constants and rates  in exercises that may some physical or social meaning.

Short Explanation

Examples show how to do formal operations on expressions  involving units. If you can see reproduce the patterns in these calculations, the longer version will be become optional or easier to follow.

Instructors:  (1) These operations with monomials involving units and their quotients  are similar to operations on monomials in variables x, y, z etc  and their quotients. The latter too (ouch) may represent formal operations on expressions that have no meaning for students other being marks on paper, albeit operations on monomials in  variables x, y, z etc could represent operations on potential calculations - the calculations that would result by replacing the variables by numbers or quantities. (2)  An operational command of calculations with units could be sufficient for further use in the representation of proportionality constants and for further use in calculation in chemistry, physics and money matters where units appear.  The short version above by itself or with further examples may provide that operational command. (3) Formal operations with monomials involving units, their products and  quotients takes on utility if not  meaning  in the subsequent appearance as rates and proportionality constants.  There-in lies a replacement or additions for examples of exponent addition and subtraction with monomials in one to several variables x, y, z, ... and their products or quotients.

Examples of Multiplication by a whole number or fraction: 

13
10

 gm2 =  13 cm2
    10 

and

12
5

  cm2
   gm5 
=  12 cm2
    5 gm5 

Example of Factoring coefficients: 

 13 cm2
    10 
13
10
* gm2

and

 8 cm2
  7 gm3 

= 8
7
cm2
   gm3 


Addition Example

Terms in which units of each are identical can be combined by adding coefficients.

5 hour2
  7 
+ 4 hour2
    7  
= [

5
7

+ 4
7
] hour2
=

9
7

 hour2
=  9 hour2
    7

and

3 cm2
  5 gm5 
+ 9 cm2
    5gm5 
= [

3
5

+ 9
5
] cm2
  gm5 
=

12
5

  cm2
   gm5 
=  12 cm2
    5 gm5 

Multiplication Example

terms need not be identical: any pair of terms can be multiplied.

7 cm2 sec3
    3 gm5 
* 9 gm9 sec4
    25 cm5 
=

7*9
3*25

gm9-5 sec3+4
    cm5-2 
= 21
25
gm4 sec7
     cm3 

Reciprocal Calculation Example: 

=         25 cm5    
9 gm9 sec4

9 gm9 sec4
    25 cm5 

Division Example

Division by a "fraction" is given by multiplication by the reciprocal of the fraction.

72 sec3
    3 gm5 
= 72 sec3
    3 gm5
*     25 cm5
9 gm9 sec4
 = 

175 
29

        cm7       
cm14 sec9


9 gm9 sec4
    25 cm5 

Pure Mathematics  (1) In the modern set-theoretic codification and axiomization of mathematics as seen in school and colleges, the codification is limited to pure numbers alone, in pairs, triplets and longer sequences, finite or infinite. Units are not discussed.  But as a service to the physical and social sciences, money matters included, the algebraic role of units in their computations can be codified or modeled using the theory of polynomials or formal power series and Laurent Expansions with real coefficients, with the formal variables being given by the units of a system of measurement.  (2) Development in one to four dimensions of the Lattice Point Codification of Product and Division Operations with Units could be an exercise with formal power series  for advanced undergraduate students of mathematitcs, those able to read  chapters I (all) and III (section 4) in Henri Cartan's work Elementary theory of analytic functions of one or several complex variables, translation of THEORIE ELEMENTAIRE DES FONCTIONS ANALYTIC D;UNE OU PLUSIEURS VARIABLES COMPLEX, to provide a codification of operation with units in which addition is limited perhaps to those monomials having the corresponding units to identical powers.  (3) Units may provide the basis of an algebra over the real (or complex numbers). Units of the same type are real (or complex) number multiples of each other.  Here changing units or changing the basis of an algebra corresponds to a  similarity transformation  on monomials with applications to similarity considerations in physical situations where computations should be and are required to be independent of the choice of units of measurement. 

 

www.whyslopes.com
Fractions, Ratios, Units, Rates & Proportionality

Fraction Starter Lesson
(simplify, multiply, divide & then add or subtract)


Area Map & Intro
Fraction Starter Lesson A
Fraction Starter Lesson B
1 What is a Fraction
2  Multiplication I
3 Multiplication II
4 Multiplication III
5 Equivalent Fractions
6. Mixed Numbers
7  Comparison
8  Addition I
9 Addition II
10 Addition III
11  Multiplication IV
12  Division
13 Two Term Ratios
14 Implied Ratios
15  Multiple Ratios
16  Units in Arithmetic
16 Longer Explanation
16 Change Units
16 Products of Quantities
16. Fractions with Units
16. Division+Reciprocals
17 Proportionality
17 Examples
18 Rates & Slopes EGs
18 Constant Rate
18 Varying Rate
18 Velocity Calc., EGs
18 Changing Units
18 Slopes and Units
18 Slopes, No Units
19 RealPlayer Videos
Links

Arithmetic Videos - Real Player Format

Decimal Addition
Methods
Decimal Subtraction Methods
Decimal Multiplication Methods
Decimal Division
Methods


Fractions
Primes
Greatest Common
Divisors

Least Common Multiples

Square Root
Simplification


Area Content Summary

  1. Fraction Starter Lesson
  2. Real Player Videos on Operations with Primes and Fractions
  3. Continuous Ruler & Line Segment
    model for fractions and operations on fractions - Number Theory Area points to the general model.
  4. Distinction between Ratios and Fractions, a nuance: While binary ratios a:b may be identified with a fraction, triple ratios a:b:c and further multiple ratios cannot.
  5. Saying how to add and subtract like monomials in units and their powers, and saying how multiply and divide like and unlike monomials leads to fraction like expressions involving units and a framework for discussion rates - ratios of quantities - a framework for handling proportionality constants, and framework for carrying units through calculation in quantitative disciplines

Hint: See site area on solving linear equations to strengthen fraction sense and algebra skills together. Good luck.


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