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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2. Solving Linear Equations
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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.


Try the Twiddla Whiteboard. In principle, it  allows to people to draw and chat together online on a copy of this webpage or a clean sheet. The chat may be via text or audio.  Visit www.twiddla.com to set up whiteboards to work with the webpage of your choice.

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.

Decimal Expansions of Fractions

Finite or Infinite & Periodic

The long division process applied to a simple fraction

M
N

will terminate before or after the decimal point and give a whole number or a decimal fraction in decimal form if the simple fraction is equivalent to a decimal fraction. 

The long division will not terminate if the simple fraction

M
N

is not equivalent to a decimal fraction.  In this case,  long division in the first gives

M = k N +r 

where the remainder r is a whole number between 1 and N-1.  The remainder r will be nonzero as we are not in the decimal fraction case. Continuing the long division process to q decimal places after the decimal point gives 

10*M = kq*N +  rq

where the q-th remainder rq is a whole number between 0 and N and is kq is a  whole number..  

Now the infinite sequence of remainders takes values in the interval [1, N-1] of whole numbers - N-1 possible values in all. Therefore the remainders must repeat. If not, the interval [1, N-1] would have infinitely values.

Pigeon Hole Principle: Now the leading N remainders rq  where 1 < q < N sequence of remainders  takes values in the interval [1, N-1] of whole numbers - N-1 possible values in all. Therefore the remainders must repeat. If not, the interval [1, N-1] would include N distinct values.  

 It follows that the decimal expansion of M/N must start repeating on or before the N first place. So the period of the decimal expansion is N or less.

Check Logic later: Am I misleading myself in the above argument?

Now for each whole number q of decimal places, the equation 

10*M = kq*N +  rq

implies 

M
---
N
 =  kq
-----

10
+ rq
-----

10

where rq is in the interval [1,N-1] repeats and eventually has period P in q, that is,   rq+P =  rq for q sufficiently large, and where km for m > q agrees with kq to q decimal places.  Therefore,

M
N

has a periodic, non-terminating decimal expansion

 aTaT-1 ....a1.b1b2b3b4b5b.... 

in which the first q decimal places are provided by the decimal fraction 

kq
-----

10

We assume that a non-terminating decimal expansion may be associated with a single point on a coordinate (half) line:

A Cauchy sequence f(n)  has the following decimal property: For each whole number k, there is a whole number N with the following property: all terms in the sequence after the first N-1 agree with each other to at least k decimal places. This property allows us to define and compute in principle an infinite decimal expansion. This expansion is assumed to define a unique real number: the limit L of the Cauchy sequence.

The limit of a repeating non-terminating, infinite decimal expansion is given by a simple fraction. For a proof, study the geometric series. 

Exercise: If two non-terminating periodic decimals differ at the k-th place in their expansion then the two decimals converge to different limits. Explain or see why.

 

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Number Theory

Start of Number Theory

Origins of Counting or Tallying
Adding Wholes
Multipling Wholes
Distributive Law  Preamble
Distributive Law for Wholes
Consequences
More Consequences
What is a Fraction
Compound Fractions

Number Theory
Continued


Decimal Place Value
Comparison Method
Addition Method
Subtraction Methods
Multiplication Methods
Division Methods
Remainder Arithmetic I
Primes & Composites
Primes Factorization
Primes & Composites
Prime Factorization Aids
Prime Factorization Examples
Counting  Whole No.  Factors
Arithmetic Videos
Square Roots
Fractions & Decimals
Fractions as Decimals
1 = 0.999 Recurring
Long Division Continued
Ratio of Simple Fractions
Ratio of Decimal Fractions
Unsigned Reals Numbers
Signed Coordinates
Plane Vectors
Horizontal Vectors
How to Add Reals
How to Multiply Reals
Distributive Law for Reals
Remainder Arithmetic II

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a 1983 McGill. Ph. D. in mathematics
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